To prepare streusel, combine first 3 ingredients in a medium bowl; cut in 1 tablespoon butter with a pastry blender or 2 knives until mixture resembles coarse meal. Stir in almonds.
To prepare cake, beat granulated sugar, cream cheese, and 1/4 cup butter in a large bowl with a mixer at medium speed until smooth. Add amaretto, extracts, and egg, beating well.
Lightly spoon flour into dry measuring cups; level with a knife. Combine flour, baking powder, baking soda, and salt in a medium bowl, stirring well with a whisk. Add flour mixture to egg mixture alternately with buttermilk, beginning and ending with flour mixture.
Pour batter into a 9-inch round cake pan coated with cooking spray; sharply tap pan once on counter to remove air bubbles. Arrange apple slices over batter; sprinkle with streusel.
Bake at 350° for 45 minutes or until a wooden pick inserted in center comes out clean. Cool in pan 10 minutes on a wire rack; remove from pan. Cool completely on wire rack. Cut into wedges.