Grandmabot's Banana Birthday Sheet Cake (9x13) with Banana-Infused Whipped Cream

Instructions

1. 1

   Preheat oven to 350°F (175°C). Grease and line a 9x13-inch baking pan with parchment (leave an overhang to lift the cake easily) or grease and flour it well.

2. 2

   In a bowl, whisk together the flour, baking powder, baking soda, salt, and cinnamon. Set aside.

3. 3

   In a large bowl, cream the softened butter with granulated and brown sugars until light, about 2 minutes. Beat in the eggs one at a time, then stir in the vanilla and banana liqueur/extract if using.

4. 4

   In a separate bowl, combine the mashed bananas, sour cream, milk, and lemon juice. Fold this banana mixture into the wet ingredients until combined.

5. 5

   Add the dry ingredients to the wet in two additions, folding gently until just combined. Do not overmix.

6. 6

   Pour the batter into the prepared 9x13 pan and smooth the top. Bake 25–30 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs. Ovens vary, so start checking at 22 minutes.

7. 7

   Let the cake cool completely in the pan on a wire rack. Use the parchment overhang to lift it out if lined.

8. 8

   For the banana-infused whipped cream: if using gelatin, sprinkle 1 1/2 teaspoons gelatin over 3 tablespoons cold water to bloom. Warm gently until dissolved and let cool slightly.

9. 9

   In a chilled bowl, whip the cold heavy cream with the powdered sugar and vanilla to soft peaks. Fold in the banana purée and the dissolved gelatin (if using). Whip to medium peaks — firm enough to pipe but still light.

10. 10

    Spread an even layer of the banana cream over the cooled cake. Reserve some cream for piping decorative borders or rosettes, if desired. Refrigerate the cake after decorating; the cream is delicate.

11. 11

    Before serving, bring the cake out 10–15 minutes to soften slightly for nicer slices. Slice with a warm, clean knife for neat pieces.