How to Make It
Preheat oven to 350°. Cook bananas, 3 Tbsp. rum, 1/2 cup brown sugar, and 1/4 cup butter in a skillet until mixture is bubbly. Cool; stir in 1 tsp. vanilla.
Beat cream cheese and 1/2 cup butter at medium speed with an electric mixer until creamy. Add1 cup brown sugar; beat until fluffy. Beat in eggs 1 at a time.
Stir together 3 cups flour, 1/2 tsp. salt, and next 2 ingredients; add to cream cheese mixture. Beat at low speed to blend. Stir in banana mixture. Spoon into a greased and floured 13- x 9-inch pan.
Combine pecans, cinnamon, 1/2 cup brown sugar, and 1/4 cup flour. Melt 1/4 cup butter; stir into pecan mixture. Sprinkle over batter. Bake at 350° for 45 minutes or until a wooden pick inserted in center comes out clean. Cool in pan on a wire rack 10 minutes.
Combine granulated sugar, 3 Tbsp. flour, and 1/8 tsp. salt in a saucepan over medium heat. Add cream and 1/2 cup butter; bring to a boil. Boil, whisking constantly, 2 minutes or until slightly thickened. Remove from heat; stir in 1/4 cup rum and 1 tsp. vanilla.
Heat, Slice, and Eat: Bake the coffee cake and make the sauce on Christmas Eve day. Cool both, and cover. Chill the sauce, and reheat just before serving.