Ingredients:
- 2 cups all-purpose flour
- 1 teaspoon baking powder
- 1/2 teaspoon baking soda
- 1/2 teaspoon salt
- 1 teaspoon ground cinnamon
- 1/4 teaspoon ground nutmeg
- 1/2 cup unsalted butter, softened
- 1/2 cup granulated sugar
- 1/2 cup brown sugar, packed
- 2 large eggs
- 1 teaspoon vanilla extract
- 1/2 cup sour cream
- 1 1/2 cups diced apples (such as Granny Smith or Honeycrisp)
- 1/2 cup chopped walnuts or pecans (optional)
- For the topping:
- 1/4 cup all-purpose flour
- 1/4 cup granulated sugar
- 1/4 cup rolled oats
- 2 tablespoons unsalted butter, softened
- 1/2 teaspoon ground cinnamon
