Gluten-Free Banana Sheet Cake

Piece of Gluten-free Banana Sheet Cake

My friend, Melanie, gave me this recipe. We frequently did bake sales together for our Boy Scout Troop Fundraiser. She would make this delicious cake. It was always a hit. It wasn’t gluten-free, however. I could never taste it. I decided I would try to convert it to be Gluten-Free. This is now one of our family favorites.


Some of my children have milk intolerance. They can do butter and our raw milk Kefir, but they can’t do most other dairy. I used the butter in this recipe, but you could try substituting it for a non-dairy butter substitute (I have not tried a substitute for the butter). I did replace the sour milk with rice milk mixed with lemon juice. It worked just fine.

Gluten-free Banana Sheet Cake just before baking.
Gluten-free Banana Sheet Cake just before baking.


I did cut down the amount of sugar that was in the recipe that Melanie gave me. I just thought it was too sweet for me the first time I made it, could be the difference in ingredients I used, but I have made it with one cup and with a cup and a quarter of sugar and they were both good. The original recipe called for a cup and a half of sugar in the batter. I use organic evaporated cane juice for my sugar.

The crowning glory of this cake is the topping. It is so simple, just sugar and chocolate. It is the alchemy that happens while it bakes that makes it so yummy. I used about 1/2 cup enjoy life mini chocolate chips and a scant 1/2 cup sugar. The topping melts and forms a crunchy layer with just the hint of chocolate that mixes with the moist banana cake flavor. Just perfection!

This cake is easy to make, so it is great for a week night dessert, taking to a bake sale, or to a potluck (will we ever get over the pandemic and be able to have bake sales, potlucks, or get togethers???….I have hope we will). You don’t need any fancy equipment to make it. I just mix it in a bowl and pour it in a 9×13 baking dish.

Gluten-free Banana Sheet Cake
Gluten-free Banana Sheet Cake

A key to baking

Anytime you bake (rather regular or gluten-free) you need to have all your ingredients at room temperature (unless the recipe says otherwise, for things like pie crust and biscuits, you want the fat cold to cut into the flour). For this recipe, you want your eggs, butter and milk to be room temperature.

Gluten-free Flour blend

I make my own gluten-free flour blends. For this cake I use a basic all-purpose blend. My blend does not have any xanthan gum in it, so I add some to the dry ingredients for the cake.

In other recipes, I have substituted psyllium husks for the xanthan gum. I haven’t tried it in this recipe, but usually I use double the amount of psyllium husks as xanthan gum. Psyllium husks work well if added into the liquids and allowed to sit for a couple of minute and then add that mixture to the dry ingredients.

Gluten-free, all-purpose flour blend
Gluten-free, all-purpose flour blend

Gluten-Free Banana Sheet Cake

Recipe by Little LisaCourse: cakes, Chocolate, Desserts and Sweets


Prep time


Cooking time






  • 1 1/2 sticks unsalted butter, softened

  • 1 cup mashed bananas (about 2 large bananas)

  • 2 eggs

  • 1/2 cup sour milk (1 teaspoon lemon juice mixed with 1/2 cup milk of choice…I use rice milk)

  • 1 cup sugar

  • 1/2 teaspoon sea salt

  • 1 teaspoon baking soda

  • 1/2 teaspoon baking powder (optional….I add it because I use rice milk which isn’t as acidic as real soured milk)

  • 2 cups gluten-free all-purpose flour blend

  • 1/2 teaspoon xanthan gum (omit if your flour blend has xanthan in it already)

  • topping:

  • 1/2 cup mini chocolate chips (I use Enjoy Life brand)

  • 1/2 cup sugar (scant 1/2 cup)


  • Grease 9×13 inch baking pan
  • Preheat oven to 325 degrees F.
  • In a small bowl, mix the mini chocolate chips and the sugar for the topping, set aside.
  • In a medium to large bowl, mix butter, bananas, eggs and milk. Mix well and break up butter into small clumps
  • In a separate bowl, mix all the dry ingredients.
  • Mix the dry ingredients into the wet ingredients. Mix really well till all combined
  • Pour batter into prepared baking pan. Sprinkle topping mixture evenly over top
  • Place into pre-heated oven and bake for 30 minutes or until top is crackly and golden and cake tester comes out clean.
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