Beat butter at medium speed with an electric mixer until creamy; gradually add sugar, beating well. Add eggs, 1 at a time, beating just until blended after each addition.
Combine flour and next 3 ingredients in a medium bowl. Add flour mixture to butter mixture alternately with buttermilk, beginning and ending with flour mixture. Stir in vanilla. Pour batter into a greased and floured 13- x 9-inch pan. Cover tightly, and chill 8 to 24 hours.
Preheat oven to 350°. Let cake stand at room temperature 30 minutes. Sprinkle with Cinnamon-Nut Crumble. Bake 32 to 35 minutes or until wooden pick inserted in center comes out clean. Sprinkle Sweet Bourbon Drizzle over cake.
Sweet Bourbon Drizzle
Stir together powdered sugar, bourbon, and 2 Tbsp. milk. Stir in remaining 1 Tbsp. milk, 1 tsp. at a time, until desired consistency. Use immediately.
COOK’S TIP: If you don’t want to use bourbon in the drizzle, substitute any extract flavor that you like, i.e. vanilla, almond, orange, etc.