Preheat oven to 350°.
To prepare topping, combine brown sugar, oats, 2 tablespoons flour, 1 tablespoon butter, and cinnamon in a small bowl. Stir in almonds; set aside.
To prepare cake, lightly spoon flour into dry measuring cups; level with a knife. Combine flour, baking soda, baking powder, and salt.
Place granulated sugar and 1/3 cup butter in a large bowl; beat with a mixer at high speed for 5 minutes or until well blended. Reduce mixer speed to medium; add eggs, 1 at a time, beating well after each addition. Add flour mixture and sour cream alternately to sugar mixture, beginning and ending with flour mixture. Stir in amaretto and pear.
Spoon batter into a 13 x 9-inch baking pan coated with cooking spray; sprinkle topping evenly over batter. Bake at 350° for 30 minutes or until a wooden pick inserted in center comes out clean. Cool in pan on a wire rack.