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
    February 28, 2018 at 8:34 am

    What a great combination of flavours! And I love that crunch you get from poppy seeds! Looks delicious, and that frosting on top- just heavenly!

  • Reply
    John / Kitchen Riffs
    February 28, 2018 at 8:25 am

    Poppy seeds and lemon? Say no more — love those two flavors together. The bananas are a bonus. 🙂

  • Reply
    February 28, 2018 at 8:02 am

    Wishing I had a piece of this cake right now with my coffee. YUM!

    • Reply
      February 28, 2018 at 8:12 am

      You caught me, I’ve got a cold slice straight from the fridge sitting next to my coffee cup!

  • Reply
    Lisa | Garlic + Zest
    February 28, 2018 at 8:00 am

    This cake looks so moist and rich I want to shove a (LARGE) piece into my mouth. And that frosting looks so creamy and luscious. I’m making this one, Sue.

  • Reply
    Becca @ Amuse Your Bouche
    February 28, 2018 at 7:45 am

    Omg that frosting looks so luscious! I love how thick you’ve spread it ;D

    • Reply
      February 28, 2018 at 7:54 am

      It’s all about the frosting to cake ratio 😉

  • Reply
    Claire | Sprinkles and Sprouts
    February 28, 2018 at 7:23 am

    Oh this looks so moist and delish!!! Especially that icing. I want to take bite!!!
    I also love the suggestion for swapping the poppy seeds for walnuts!! I think that would go down so well with my kids for afternoon tea!

    • Reply
      February 28, 2018 at 7:29 am

      This is a perfect tea cake, thanks Claire.

  • Reply
    Jennifer @ Seasons and Suppers
    February 28, 2018 at 4:53 am

    Loving the lemon buttercream here! And the banana cake looks perfect. Craving 🙂

    • Reply
      February 28, 2018 at 6:59 am

      A little lemon buttercream never hurts 😉

  • Reply
    Tricia @ Saving Room for Dessert
    February 28, 2018 at 4:50 am

    This lovely cake sure would be good with my coffee this morning! What a terrific flavor combination and that buttercream looks dreamy! Sharing and pinning 🙂

  • Reply
    Chris Scheuer
    February 28, 2018 at 3:57 am

    Hmmm, would it be legal to have this for breakfast? It looks so good I want it now! And certainly easy enough to make before anyone else is awake! Pinning and sharing!

    • Reply
      February 28, 2018 at 6:51 am

      Of course I was going to mention that I’ve already had it for breakfast…twice. But I thought that might be inappropriate 😉

  • Reply
    [email protected]'s Recipes
    February 28, 2018 at 3:26 am

    I do love adding poppy into the banana cake batter. Your version with lemon buttercream looks fabulous, Sue.

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