Banana-Caramel Cake

Ingredients

• 1 1/2 tsp. vanilla extract
• 1/2 tsp. lemon juice
• 1/2 tsp. salt
• 1 1/2 c. heavy cream
• 1 1/4 c. granulated sugar
• 1 c. very ripe, mashed bananas
• 5 tbsp. cold butter, cut into pieces
• 1/2 c. buttermilk
• 2 large eggs
• 1/2 tsp. baking soda
• 3 c. light brown sugar
• 2 1/2 tsp. baking powder
• 1/2 c. unsalted butter, softened, plus more for pans
• 2 1/2 c. cake flour, plus more for pans