For the cake:
3 cups all-purpose flour
2 teaspoons baking soda
1/2 teaspoon salt
2 sticks (8 ounces) unsalted butter, at room temperature
2 cups sugar
2 teaspoons pure vanilla extract
2 large eggs, preferably at room temperature
About 4 very ripe bananas, mashed (you should have 1 1/2 – 1 3/4 cups)
1 cup sour cream or plain yogurt
Center a rack in the oven and preheat to 350 degrees F. Generously butter a 9- to 10-inch (12 cup) Bundt pan. (If you use a silicone Bundt pan there’s no need to butter it.) Don’t place the pan on a baking sheet – you want the oven’s heat to circulate through the Bundt’s inner tube.
Whisk the flour, baking soda and salt together.
Working with a stand mixer, preferably fitted with a paddle attachment, or with a hand mixer in a large bowl, beat the butter until creamy. Add the sugar and beat at medium speed until pale and fluffy. Beat in the vanilla, then add the eggs one at a time, beating for about 1 minute after each egg goes in. Reduce the mixer speed to low and mix in the bananas. Finally, mix in half the dry ingredients (don’t be disturbed when the batter curdles), all the sour cream and then the rest of the flour mixture. Scrape the batter into the pan, rap the pan on the counter to debubble the batter and smooth the top.
Bake for 65 to 75 minutes, or until a thin knife inserted deep into the center of the cake comes out clean. Check the cake after about 30 minutes – if it is browning too quickly, cover it loosely with a foil tent. Transfer the cake to a rack and cool for 10 minutes before unmolding onto the rack to cool to room temperature.
For the icing:
1/2 cup butter
3 cups powdered sugar, sifted
2 teaspoons vanilla
2 tablespoons milk
2 tablespoons dark rum
In a medium bowl, add powdered sugar.
Place butter in a small saucepan. Melt butter over medium heat until bubbly. Cook, stirring occasionally until golden brown.
Remove from heat and pour butter into the bowl of powdered sugar. Add milk and vanilla, stir until smooth.