To prepare cake, place granulated sugar, 3 tablespoons butter, and cream cheese in a large bowl; beat with a mixer at medium speed until well blended (about 5 minutes).
Add egg and egg white, 1 at a time, beating well after each addition. Beat in vanilla. Lightly spoon flour into dry measuring cups; level with a knife.
Combine flour, baking powder, baking soda, and salt, stirring well with a whisk.
Add flour mixture and buttermilk alternately to sugar mixture, beginning and ending with flour mixture.
Pour batter into a 9-inch round cake pan coated with cooking spray.
Bake at 350 for 30 minutes or until wooden pick inserted in center comes out clean.
Remove cake from oven. Reduce oven temperature to 32
To prepare topping, combine syrup, brown sugar, and 2 tablespoons butter in a 4-cup glass measure. Microwave at high 1 minute. Stir with a whisk until butter melts.
Whisk in pecans and beaten egg.
Using a wooden skewer, poke holes in top of warm cake.
Pour pecan mixture over top of cake. Return cake to oven; bake at 325 for 10 minutes. Cool completely on wire rack.