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
3.90 from 69 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
    March 2, 2021 at 10:00 am

    Made the cake. Loved it!! But I have one question: I wondered when I was putting it together why only l/2 tsp of baking soda. My cake did not raise and was still great, but very dense. Some of your pictures show cakes that have risen and some looking like my cake…unraised. I am considering doubling the baking soda next time. Yes, there will be a next time, delicious. Any suggestions?

  • Reply
    February 11, 2021 at 12:44 pm

    Hi Sue, I was looking at two of your Banana Poppy Seed Cake recipes today. This one calls for a 9″ x 9″ square baking pan. The other one with identical ingredients calls for a 8″ x 8″ square baking pan. Is one of these a typing error? Does it matter which size baking pan?
    I can hardly wait to make this cake!

    • Reply
      Sue Moran
      February 11, 2021 at 1:56 pm

      They were made years apart, and I just used a different pan, so you can use either. It’s quite a thin cake, almost like a blondie, so depending on your pan it might be a little thicker.

  • Reply
    May 11, 2020 at 12:33 pm

    5 stars
    Really yummy and didn’t even get it iced:)

    • Reply
      May 11, 2020 at 1:12 pm

      The icing is my favorite part!

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