Preheat Your Oven: Start by preheating your oven to 350°F (175°C). This ensures your cake bakes evenly and rises perfectly.

Prepare Your Baking Pan: Grease and flour a 9x13-inch baking pan (or line it with parchment paper) to prevent the cake from sticking.

Mash the Bananas: In a medium bowl, mash your ripe bananas with a fork or potato masher. You want a smooth, mashed consistency with a few small chunks for texture. Set aside.

Cream the Butter and Sugar: In a large mixing bowl, beat the softened butter and granulated sugar together using an electric mixer on medium speed until light and fluffy (about 3-4 minutes). This helps incorporate air into the batter for a fluffy cake.

Add Eggs and Vanilla: Add the eggs, one at a time, beating well after each addition. Stir in the vanilla extract. The mixture should look smooth and creamy.

Mix the Dry Ingredients: In a separate bowl, whisk together the flour, baking soda, salt, and cinnamon (if using). This ensures the baking soda is evenly distributed throughout the flour for even leavening.

Combine the Wet and Dry Ingredients: Gradually add the dry ingredients to the wet mixture, alternating with the buttermilk. Start with a third of the flour mixture, then half of the buttermilk, and continue alternating until everything is mixed in. Be careful not to overmix—just stir until combined.

Add the Bananas: Gently fold in the mashed bananas until evenly distributed throughout the batter. You’ll see the banana flavor and moisture coming through!

Bake: Pour the batter into the prepared baking pan and spread it out evenly. Bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean. Keep an eye on it towards the end to avoid overbaking.

Cool and Serve: Let the cake cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely. Once cooled, serve as is or top with your favorite frosting.