Gluten-free Banana Nut Sourdough Coffee Cake
Nothing like a super easy, tasty, and classic coffee cake to start your Sunday morning off right!
Equipment
- 10 x 13-inch pan
- Electric Hand Mixer or Kitchen Stand Mixer
- Spatula
- Mixing Bowls
- Kitchen Scale
- Measuring Cups & Spoons
- Cake Tester
Ingredients
Dry Mixture, Part I
- 288 g (2⅓ Cups) Gluten Free Baking Flour Bob's Red Mill 1-to-1
- 116 g (½ Cup) Sugar Granulated
- 5 g (½ tsp) Sea Salt Fine
Topping Mixture
- 88 g (⅔ Cup) Dry Mixture, Part I
- 10 g (¼ Cup) Gluten-free quick cooking oats
- 5 g (1 Tsp) Light Brown Sugar
- 4 g (½ Tsp) Ground Cinnamon
- 4-5 g (1 Tsp) Walnut Oil
- 14 g (1 Tbsp) Unsalted butter, room temperature
- 30 g (¼ Cup) Walnuts chopped (not roasted)
Dry Mixture, Part II
- 30 g (¼ Cup) Gluten-free quick-cooking oats
- 10 g Tapioca Flour (Starch)
- 6 g (1¼ Teaspoon) Baking Soda
- 4 g (¾ Teaspoon) Baking Powder
- 140 g (1⅓ Cup) Walnuts Chopped and ideally roasted
Wet Mixture
- 100 g (8 Tbsp) Unsalted butter, melted and cooled
- 174 g (⅞ Cup) Light Brown Sugar
- 2 large Eggs
- 350 g (3-4 peeled) Bananas (3-4) Ripe and mashed
- 174 g (1 Cup) Gluten-free Sourdough Starter (discard)
Instructions
Before You Begin
- Preheat the oven to 350 F / 176 C
- Grease a 10 x 13-inch pan
- I find it's super helpful to measure out all the wet ingredients in the beginning since it's best if they are all at room temperature when you mix.
- Melt the butter so it has time to cool
- Roast the walnuts for the Dry Mix, Part II on low-medium heat to get them a little crispy.
START THE DRY MIXTURE
- Whisk together the flour, sea salt, and granulated sugar into a small to medium-sized mixing bowl.
- Take out and put 88 g (⅔ Cup) of the dry mixture into a small to medium-sized bowl. Adjust amount if doubling or tripling the recipe.
MAKE TOPPING MIXTURE
- Add oats, 1 tsp of light brown sugar, cinnamon, walnut oil and butter to the 88g of dry mix.
- Mash together with a fork until the butter is evenly incorporated. Small little clumps is OK.
- Toss in chopped walnuts and set aside.
FINISH THE DRY MIXTURE
- Return to your dry mix, add the quick oats, tapioca starch, baking soda, and baking powder and whisk until well combined.
- Toss in the chopped nuts and mix until evenly incorporated.
START THE WET MIXTURE
- In a separate, larger bowl, cream together the melted (and cooled) butter with the light brown sugar for a 1-2 minutes, so that it's nice and creamy.
- Add the eggs and whisk on high for about 5, maybe even 7, minutes, so long as it is pale, fluffy and has a nice sheen.
- Add the sourdough starter by breaking it up into chunks and then whisking on high until there are only small lumps.
- Now mash those bananas, separately, and add to the wet mix, only whisking on high until incorporated.
COMBINE MIXTURES
- Tip! Be careful not to over mix the dry ingredients in the wet mix. (You don't want to lose all the air you got from whisking those eggs in!)
- Gradually (I like to add the dry mix in 3 rounds) and gently add the dry mixture to the wet mixture. Ideally, it should be more of a folding motion rather than a mixing or stirring one.
- Pour the batter evenly and gently into a well-greased pan.
- Tip! For the topping, I like to spread a little of the topping all over, then I go back over to make sure I can get it up to the edges. I even go back and "puncture" the batter so that I mix a little of the topping into the batter bit to add more flavor and texture.
BAKING
- I like to make sure the oven has been at desired temperature for at least a half-hour before baking.
- Place the pan in the middle of the rack, in the upper half of the oven and bake for 25-30 minutes.
- You'll know it's ready when you poke a toothpick or cake tester into the middle and it comes out clean.
- Cool for 10 minutes before serving, and enjoy!
Nutrition
Serving: 1Slice | Calories: 303kcal | Carbohydrates: 42g | Protein: 5g | Fat: 15g | Saturated Fat: 5g | Trans Fat: 1g | Cholesterol: 39mg | Sodium: 264mg | Potassium: 161mg | Fiber: 4g | Sugar: 22g | Vitamin A: 229IU | Vitamin C: 2mg | Calcium: 58mg | Iron: 1mg