1. Preheat oven to 350.

2. To prepare cake, coat a 10-inch tube pan with cooking spray; dust with breadcrumbs. Set aside.

3. Lightly spoon flour into dry measuring cups; level with a knife. Combine flour, baking powder, baking soda and salt, stirring well with a mixer at medium speed until light and fluffy. Add eggs, 1 at a time, beating well after each addition. Add milk, 1 tablespoon rum, and vanilla; beat until combined. Beating at low speed, add flour mixture and sour cream alternately to sugar mixture, beginning and ending with flour mixture; beat until just combined.

4. Spoon batter into prepared pan. Bake at 350 for 1 hour or until a toothpick comes out clean. Cool in pan 10 minutes. Loosen cake from sides of pan using a narrow metal spatula. Place a plate upside down on top of cake; invert onto plate. Invert cake again. Pierce cake liberally with a wooden pick.

5. While cake bakes, prepare glaze. Combine brown sugar, 2 tablespoons rum, and water in a small saucepan; bring to a boil, stirring until sugar dissolves. Add 1 1/2 tablespoons butter, stirring until butter melts. Drizzle half of warm glaze evenly over warm cake; allow mixture to absorb into cake. Drizzle remaining glaze over cake. Cool cake completey.