1cup (2 sticks)unsalted butter,at room temperature
2cupsgranulated white sugar
1½ to 1¾cupsmashed very ripe bananas
1cupsour cream or plain yogurt
CREAM CHEESE FROSTING (optional):
4ouncescream cheese,at room temperature
1 to 2tablespoonsmilk(as needed, to thin out)
PREPARE THE CAKE:
Center a rack in the oven and preheat the oven to 350°F. Generously butter a 9 to 10-inch (12 cup) bundt pan.
In a medium bowl, whisk together the flour, baking soda and salt.
In a large bowl, use an electric mixer to 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 speed to low and mix in the bananas. Finally, mix in half of 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 de-bubble the batter and smooth the top.
Bake 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.
If you've got time, wrap the cooled cake in plastic and allow it to sit on the counter overnight before serving- it's better the next day.
MAKE THE CREAM CHEESE FROSTING:
Use an electric mixer to blend together the frosting ingredients. Add just enough milk to make the glaze thin enough so that it will drip down the sides of the cake, but not so thin that it will drip off of the cake. If you accidentally get it too thin, just add more powdered sugar. Spoon the glaze onto the top of the cake and let it ooze down the sides.
*Wrapped airtight, the cake will keep at room temperature for up to 5 days or in the freezer for up to 2 months.