Oatmeal-Banana Coffee Cake

Ingredients

• vegetable oil cooking spray
• 1/3 cup milk
• 2 teaspoons white vinegar
• 2 ripe bananas
• 0.75 cup all-purpose flour
• 0.75 cup whole wheat flour
• 0.75 cup rolled oats
• 1 teaspoon baking powder
• 0.75 teaspoon baking soda
• 0.5 teaspoon salt
• 0.5 cup unsalted butter, at room temperature
• 0.5 cup brown sugar
• 2 large eggs
• 1 teaspoon vanilla extract
• Topping:
• 1/3 cup packed brown sugar
• 3 tablespoons all-purpose flour
• 2 tablespoons unsalted butter, softened
• 0.25 cup chopped pecans

Steps

1. Preheat the oven to 375 degrees F (190 degrees C). Spray a 10-inch square baking pan with cooking spray.
2. Combine milk and vinegar in a glass to make sour milk; stir gently. Mash bananas in a small bowl to make 1 cup.
3. Combine all-purpose flour, whole wheat flour, oats, baking powder, baking soda, and salt in a bowl.
4. Cream butter and brown sugar in a large mixing bowl with an electric mixer until fluffy. Beat in eggs and vanilla extract. Mix in bananas. Add dry ingredients in 2 batches, alternating with sour milk; mix thoroughly. Pour batter into the prepared pan.
5. Mix brown sugar, flour, and butter for topping together in a bowl. Sprinkle topping over batter, then sprinkle on pecans.
6. Bake in the preheated oven until a toothpick inserted into the center comes out clean, 25 to 30 minutes. Cool on a wire rack before cutting into squares.