Banana Poppy Seed Cake with Lemon Buttercream

A piece of banana cake on a plate, with frosting

Banana Poppy Seed Cake with Lemon Buttercream ~ snack time just got a whole lot more interesting with this unique combination of bananas, poppy seeds, and lemon ~ you can whip up this easy one bowl cake in no time.

Banana Poppy Seed Cake with Lemon Buttercream, sliced on parchment paper

Banana Poppy Seed Cake is the perfect snack cake

When you’re ready for a change from the same old banana bread, this cake really hits the spot. You won’t be expecting the crunch of the poppy seeds or the tang from the lemon frosting, but they’re lovely! If you’re going to share it, be sure to have copies of the recipe ready to go, you’re gonna get asked.

A piece of Banana Poppy Seed Cake with fork on a wooden table

This is a classic dense and moist banana cake with the footprint of a blondie

I don’t know why I haven’t thought to combine all these elements together before, they make for a cake that’s unusual but familiar at the same time.

What you’ll need:

  • ripe bananas
  • butter ~ unsalted and room temperature
  • sugar ~ granulated
  • sour cream
  • egg
  • flour ~ all purpose
  • poppy seeds
  • vanilla extract
  • salt and baking soda
  • confectioner’s sugar
  • lemon juice


Banana Poppy Seed Cake with Lemon Buttercream on a wooden table

How to whip this one bowl banana cake up

No need to haul out the heavy equipment for this banana snack cake ~ just a whisk and a bowl will do fine.

  • Cream the butter, sugar, and sour cream together until light and fluffy.
  • Beat in the egg, mashed banana, poppy seeds, and vanilla.
  • Add the dry ingredients and whisk just until blended.
  • Bake!

Banana Poppy Seed Cake batter

Lemon buttercream sets this easy banana cake apart from the rest

I’m generous with this particular frosting, which has a similar tangy quality to a cream cheese frosting, but it’s even easier to whip up. You might know it from my Blueberry Zucchini Cake with Lemon Buttercream. It’s butter-heavy, and because of that I think it tastes best chilled, so I keep my cake in the refrigerator until I’m ready to eat.

Banana Poppy Seed Cake with poppy seeds

It’s no secret that I love poppy seeds ~ I use them all the time, in everything from Lemon Poppy Seed Pancakes to Chicken Salad with Poppy Seed Mayonnaise. They just add that special touch to so many foods. I buy them in bulk, which means I always have some on hand to add to my recipes.

Ingredient spotlight: BULK POPPY SEEDS

poppy seeds in a jar


If your local store doesn’t carry them, you can find poppy seeds in bulk, online, HERE. To store extra poppy seeds, put them in an airtight container in the refrigerator (6 mos) or freeze them, (1 year).


slices of banana poppy seed cake on a knife

Reader Rave ~

“Absolutely amazing. I now have to gift the rest of it so I won’t eat anymore. I did use zest in the frosting. It was perfect.” ~ Leia

A piece of banana cake on a plate, with frosting
3.89 from 68 votes

Banana Poppy Seed Cake with Lemon Buttercream

Banana Poppy Seed Cake with Lemon Buttercream is an easy one bowl snack cake generously topped with an irresistible lemon frosting!
Course Dessert
Cuisine American
Prep Time 15 minutes
Cook Time 35 minutes
Total Time 50 minutes
Yield 12 servings
Calories 299kcal
Author Sue Moran


  • 2 Tbsp unsalted butter at room temperature
  • 2/3 cup sugar
  • 1/2 cup sour cream
  • 1 large egg room temperature
  • 2-3 ripe bananas mashed (to make about 3/4 cup mashed)
  • 1/3 cup poppy seeds
  • 1 tsp vanilla extract
  • 1 cup flour
  • 1/4 teaspoon salt
  • 1/2 teaspoon baking soda

lemon buttercream

  • 8 Tbsp 1 stick, 1/2 cup unsalted butter, at room temperature
  • 2 cups confectioner's sugar
  • juice of 1 lemon about 2 Tbsp
  • the tiniest drop of yellow food coloring optional


  • Set oven to 350F Lightly spray a 9x9 square baking pan. I like to line it with parchment paper so I can lift the cake out after baking for easy frosting and cutting.
  • Cream the butter, sugar, and sour cream together until light and fluffy. Beat in the egg, mashed banana, poppy seeds, and vanilla.
  • Whisk the flour, salt, and baking soda together and add to the wet ingredients. Mix until just blended.
  • Turn the batter out into the pan and smooth out evenly. Bake for about 35 minutes, or until the top is just turning golden and the middle is set. A toothpick inserted in the center should be free of wet batter.
  • Let cool on a rack completely before frosting.
  • Make the frosting by beating the butter and sugar together with the lemon juice and food coloring, if using. Add a touch more juice if the frosting is too thick, or a little more sugar if too thin.
  • I like to store the cake in the refrigerator, and it will keep for up to a week.

Cook's notes


  • Add the zest of the lemon to the frosting if you like for even more lemony flavor.
  • Substitute chopped walnuts or pecans for the poppy seeds.
  • Substitute cream cheese for the butter in the frosting.


Calories: 299kcal | Carbohydrates: 45g | Protein: 3g | Fat: 13g | Saturated Fat: 7g | Trans Fat: 1g | Cholesterol: 44mg | Sodium: 110mg | Potassium: 124mg | Fiber: 1g | Sugar: 34g | Vitamin A: 384IU | Vitamin C: 2mg | Calcium: 58mg | Iron: 1mg
The nutritional information for recipes on this site is provided as a courtesy and although tries to provide accurate nutritional information, these figures are only estimates.

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    Leave a Reply

    Please rate this recipe!

  • Reply
    May 6, 2020 at 4:26 pm

    4 stars
    I used Cup 4 Cup gluten free flour, and it was tasty but probably a little denser and darker colored than yours looked in the pictures. I always have extra bananas and usually have poppy seeds as well, so I think I will try it again but with a different gluten free flour blend. One never knows. It just looked so divine that I had to try it.

  • Reply
    Penny O’Brien
    February 22, 2020 at 11:38 am

    5 stars
    This cake is sooooo delicious! Will now be one of my special desserts for lunch/dinner guests. I don’t like a lot of icing so I halved the icing amount, and it was just fine. And I did use a lemon for the juice, not from a bottle. Thank you so much.

  • Reply
    Mark Abel
    August 12, 2019 at 11:24 am

    I made this yesterday, it’s very good. The lemon frosting goes wonderful with it. Great for using those old bananas. Cake part seemed really heavy, but we both loved it.

    • Reply
      August 12, 2019 at 11:43 am

      Thanks Mark 🙂

  • Reply
    June 14, 2019 at 11:54 am

    Hello! I am planning on making this for father’s day, and I was wondering if you could include a metric version of the ingredients? Also, how important is the sour cream? I don’t have any in the house, so I would be grateful for any other substitutions.

    • Reply
      January 10, 2020 at 8:14 pm

      Typically I will substitute buttermilk, half and half, or even yogurt for sour cream if necessary.

  • Reply
    August 27, 2018 at 5:54 pm

    Hi Sue,
    Do you think this recipe would work in muffin form instead of a cake?
    Thanks in advance!

    • Reply
      August 27, 2018 at 6:06 pm

      I’m sure you could bake it that way Cecily, just be aware that it would be a dense type of muffin, not fluffy. The cake is sort of blondie-like in texture.

  • Reply
    June 5, 2018 at 5:25 am

    Hi, just wondering what kind of flour should be used for this; plain or self-raising flour?

    • Reply
      June 5, 2018 at 6:55 am

      I use plain all purpose flour, Verity.

  • Reply
    May 10, 2018 at 2:15 pm

    5 stars
    Lovely recipe thank you . I used ground almonds instead of flour and it was very moist and light.

    • Reply
      May 10, 2018 at 2:38 pm

      Thanks Eugene, that’s great to know about the gf option!

  • Reply
    April 1, 2018 at 5:57 pm

    5 stars
    I made this to have for Easter morning breakfast since I wanted something special but we didn’t have much time before rushing off to church. I knew the frosting and bananas would add sweetness, so I halved the sugar. I don’t typically buy sour cream, but always have whole milk yogurt on hand, so that’s what I subbed. Poppy seeds, 1/4c. I replied to someone else that, yes, using gluten-free flour works nicely. The only other change was to use some of the frosting the I already made for a carrot cake, which was a maple cream cheese frosting. We all loved it! Such a nice variation of a banana bread. Adding this to my favorites!

    • Reply
      April 2, 2018 at 7:03 am

      Thanks for the feedback, Karla, and I’m glad to know that the yogurt worked well. I LOVE the sound of that maple cream cheese frosting, I’m definitely going to steal that idea from you 😉

  • Reply
    March 15, 2018 at 4:03 am

    5 stars
    Absolutely amazing. I now have to gift the rest of it so I won’t eat anymore. I did use zest in the frosting. It was perfect.

  • Reply
    March 10, 2018 at 7:12 pm

    Can I use prepared poppy seeds in a tin or do you use dry ?
    Looks so good

    • Reply
      March 10, 2018 at 7:17 pm

      I used dry, Lou, but I wonder if you might be able to use the prepared seeds in place of the dry mixed with the cream. I don’t imagine it would taste quite as good, because the canned stuff has mostly added sugar.

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