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Crazy Banana Cake

Crazy banana cake (wacky banana cake) is an easy, one-bowl, egg-free banana sheet cake with a spongy, airy crumb. A simple chocolate glaze is poured over the warm cake so it soaks in for a lightly fudgy top.
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Prep Time 15 minutes
Cook Time 30 minutes
Total Time 45 minutes
Servings: 12 servings
Course: Dessert
Cuisine: American
Calories: 420
Ingredients Equipment Method Notes

Ingredients
  

Banana cake base
  • 3 ripe bananas
  • 1.5 cup all-purpose flour
  • 1 cup sugar
  • 1 tsp baking soda
  • 0.5 tsp salt
  • 1 tsp cinnamon
  • 0.33 cup vegetable oil
  • 1 tbsp apple cider vinegar
  • 1 tsp vanilla extract
  • 0.5 cup water
Chocolate glaze
  • 1 cup powdered sugar
  • 3 tbsp cocoa powder
  • 3 tbsp milk
  • 0.5 tsp vanilla

Equipment

  • 1 sheet pan

Method
 

Bake the cake
  1. Preheat oven to 350°F and grease a 9x13 pan with a thin, even coating for easy release.
  2. Mix all-purpose flour, sugar, baking soda, salt, and cinnamon directly in the pan until the dry ingredients are evenly combined and look uniform.
  3. Make three wells in the flour mixture so they’re clearly separated and can hold the wet ingredients without overflowing.
  4. Add vegetable oil to one well, apple cider vinegar to the second well, and vanilla extract to the third well.
  5. Pour mashed ripe bananas and water over everything so the liquid reaches the dry areas throughout.
  6. Stir with a fork just until combined, stopping as soon as there are no large dry pockets for a tender crumb.
  7. Bake for 25–30 minutes at 350°F until a toothpick comes out clean; avoid overbaking to keep the cake spongy.
Glaze and serve
  1. Whisk powdered sugar, cocoa powder, milk, and vanilla until smooth, with no lumps.
  2. Pour the chocolate glaze over the warm cake so it runs toward the edges and soaks into the crumb.

Notes

Pro tip: bake only until a toothpick comes out clean (a minute or two too long can dry out the spongy crumb). Store covered in the fridge up to 4 days. Freeze slices up to 2 months, thaw overnight in the refrigerator. For a dairy-free option, use a dairy-free milk (such as unsweetened oat or soy) in the chocolate glaze.