1/2 cup plus 2 tablespoons unsalted butter, softened, divided
1 cup sugar
2 large eggs, room temperature
1 teaspoon vanilla extract
2 cups all-purpose flour
1 teaspoon baking soda
1 teaspoon baking powder
1/2 teaspoon salt
1 cup sour cream
1 medium apple, peeled and finely chopped
1 medium pear, peeled and finely chopped
1 cup packed brown sugar
1 teaspoon ground cinnamon
1/2 cup chopped walnuts or pecans
Preheat oven to 350°. Grease a 13x9-in. baking pan. In a large bowl, cream 1/2 cup butter and the sugar until light and fluffy, 5-7 minutes. Add eggs, 1 at a time, beating well after each addition. Beat in vanilla. In another bowl, whisk flour, baking soda, baking powder and salt; add to creamed mixture alternately with sour cream, beating well after each addition. Fold in apple and pear. Transfer to prepared pan.
For topping, combine brown sugar, remaining 2 tablespoons butter and the cinnamon in a small bowl; mix with a fork until crumbly. Stir in nuts. Sprinkle over batter. Bake until a toothpick inserted in center comes out clean, 30-35 minutes. Cool slightly in pan on a wire rack.