Do not sprinkle cake with powdered sugar. Wrap cooled cake in plastic wrap; overwrap tightly with foil. Freeze for up to 1 month. Thaw overnight at room temperature. Before serving, sprinkle with powdered sugar.
Blogger Variation by Alejandra Ramos of Always Order Dessert
For Alejandra's version, prepare as above, except add 1 tablespoon ground Saigon cinnamon and a pinch of kosher salt to the flour mixture in Step 1. In Step 2, omit brown sugar and use 1 cup granulated sugar. While the cake cools, in a large saucepan combine 1/2 cup unsalted butter, 1/2 cup water, 3/4 cup granulated sugar, 1/4 teaspoon kosher salt, and 3 3-inch cinnamon sticks. Bring to boiling, stirring to dissolve sugar. Reduce heat and simmer, uncovered, for 5 to 7 minutes or until reduced to about 1 cup, stirring occasionally. Remove from heat. Remove and discard cinnamon sticks. Stir in 1/2 cup light rum. Wash and dry the same fluted tube pan and coat with nonstick spray for baking. Return cake to pan. Pour hot syrup over cake. Cover and let stand for 4 to 24 hours. Remove from pan and sprinkle with powdered sugar and additional cinnamon just before serving.