Banana cake

2 cups all purpose flour 1 teaspoon baking soda 1 teaspoon cinnamon 1/2 teaspoon salt 1/2 cup (1 stick) unsalted butter 1 cup white granulated sugar 1/2 cup brown sugar 2 eggs The scraped insides of one vanilla bean or 1 teaspoon of vanilla extract 1 cup of mashed ripe bananas (2 large or 3 medium bananas) 1/2 cup full fat sour cream Frosting 6 ounces cream cheese, room temp 4 Tbsp (1/4 cup) unsalted butter, room temp 2 cups powdered sugar 1 teaspoon vanilla extract 1 teaspoon lemon juice Preheat the oven to 350°F (175°C) . In a medium bowl, whisk together the flour, baking soda, cinnamon, and salt. Beat together in a mixer the butter and sugars. Beat in the eggs one at a time. Mix in the vanilla and mashed bananas. Mix in half of the flour mixture, then the sour cream, then the other half of the flour mixture. Spread batter evenly in a greased 10x15 baking pan. Bake at 350°F (175°C) for 20 minutes, or until nicely browned and the surface bounces back when you press it with your finger. Cool completely before frosting. To make the frosting, mix all of the ingredients together with an electric mixer. If too stiff to spread, add a teaspoon or two of water. Spread the frosting evenly over the cake and slice to serve.