# Ingredient List:
→ Cake
01 - 2 cups all-purpose flour
02 - 1 ½ teaspoons baking powder
03 - ½ teaspoon baking soda
04 - ½ teaspoon salt
05 - 1 teaspoon ground cinnamon
06 - ½ cup unsalted butter, softened
07 - ¾ cup granulated sugar
08 - 2 large eggs
09 - 1 teaspoon vanilla extract
10 - 1 cup sour cream
11 - 2 medium apples, peeled, cored, and diced (about 2 cups)
→ Streusel Topping
12 - ⅔ cup all-purpose flour
13 - ⅓ cup brown sugar
14 - ½ teaspoon ground cinnamon
15 - ¼ teaspoon salt
16 - 5 tablespoons unsalted butter, melted
→ Glaze (optional)
17 - ½ cup powdered sugar
18 - 1 to 2 tablespoons milk
# Steps:
01 - Set oven to 350°F. Grease a 9-inch square baking pan or line it with parchment paper.
02 - Combine flour, brown sugar, cinnamon, and salt in a bowl. Stir in melted butter until crumbly. Set aside.
03 - In a large bowl, whisk together flour, baking powder, baking soda, salt, and cinnamon.
04 - In a separate bowl, beat softened butter and sugar until light and fluffy. Add eggs one at a time, then mix in vanilla extract.
05 - Blend sour cream into the wet mixture until smooth.
06 - Fold dry ingredients into the wet mixture gently until just combined; avoid overmixing.
07 - Carefully fold diced apples into the batter.
08 - Spread batter evenly in prepared pan and sprinkle streusel topping over it.
09 - Bake for 38 to 42 minutes until golden and a toothpick inserted in the center comes out clean.
10 - Let cool in pan for 15 minutes. For glaze, whisk powdered sugar with milk until smooth and drizzle over cooled cake if desired.
11 - Serve warm or at room temperature.
