Banana Crumb Mug Cake

If you've ever found yourself craving banana bread but didn't want to make an entire loaf, this Banana Crumb Mug Cake is exactly what you need. It's soft, fluffy, packed with sweet banana flavor, and topped with an irresistible buttery cinnamon crumb topping that bakes into the most delicious little crumble.

Finished with a simple vanilla glaze, this single-serving dessert tastes like a cross between homemade banana bread and your favorite bakery crumb cake. The best part? It's ready in about 30 minutes from start to finish, making it perfect for an afternoon treat, late-night dessert, or whenever you have one lonely ripe banana sitting on the counter.

This recipe is the newest addition to my mug cake series, and I think it might be one of my favorites yet. If you've already tried my Cheesecake Brownie Batter Baked Oats or Carrot Cake Mug Cake, this cozy banana version is the perfect one to bake next.

Banana Crumb Mug Cake Ingredients

All-purpose flour – Gives the mug cake structure while keeping it soft.

Brown sugar and granulated sugar – Using both adds moisture while giving the cake a deeper caramel-like sweetness.

Baking powder – Helps the cake rise into a fluffy, tender crumb.

Ground cinnamon – Adds warmth and pairs perfectly with banana.

Salt – Balances the sweetness and enhances the flavor.

Mashed ripe banana – The riper the banana, the sweeter and more flavorful your mug cake will be.

Vegetable oil – Keeps the cake incredibly moist.

Greek yogurt – Adds richness and tenderness without making the cake heavy.

Milk – Helps create a smooth batter.

Vanilla extract – Brings all the flavors together.

How to Make Banana Crumb Mug Cake

Step 1: Make the crumb topping

Combine the flour, brown sugar, cinnamon, and melted butter until large crumbs form. Set aside while you prepare the cake batter.

Step 2: Mix the batter

Whisk together the dry ingredients before stirring in the banana, oil, Greek yogurt, milk, and vanilla until just combined.

Step 3: Assemble

Pour the batter into a greased oven-safe ramekin and generously sprinkle the crumb topping over the surface.

Step 4: Bake

Bake at 350°F for 20–25 minutes, or until the center is set and a toothpick comes out with a few moist crumbs.

Step 5: Glaze and enjoy

Let the mug cake cool for about 10 minutes before drizzling with the vanilla glaze.

Serve warm and enjoy every buttery, crumb-filled bite.

Tips for the Best Banana Crumb Mug Cake

• Use a very ripe banana for the sweetest flavor.
• Don't overmix the batter or the cake can become dense.
• Leave plenty of large crumbs instead of mixing them into a fine sand. Bigger crumbs create the best texture.
• Bake until the center is just set. Overbaking can dry out the cake.

Variations

Add chocolate chips: Fold a handful of mini chocolate chips into the batter for a chocolate banana version.

Add nuts: Chopped pecans or walnuts add a delicious crunch.

Make it extra cozy: Add a pinch of nutmeg or pumpkin pie spice to the batter.

Frequently Asked Questions

What size ramekin should I use?

A 10- to 12-ounce oven-safe ramekin works best. It gives the cake room to rise while keeping it thick and fluffy.

Can I make this ahead of time?

This mug cake is best enjoyed warm on the day it's baked, but leftovers can be covered and stored in the refrigerator for up to 2 days.

Can I use sour cream instead of Greek yogurt?

Yes! Sour cream works as a 1:1 substitute and creates an equally moist cake.

Can I microwave this instead?

This recipe was specifically developed for the oven, which creates a much softer texture and allows the crumb topping to become perfectly crisp.

Storage

Cover leftovers tightly and refrigerate for up to 2 days.

Warm in the microwave for 15–20 seconds before serving. Add a little extra glaze if desired.

If you make this Banana Crumb Mug Cake I would really appreciate a comment and rating down below, under the recipe card. Don’t forget to take a picture and tag me over on Instagram, Tik Tok, or Pinterest. For more ideas, check out my Dessert Recipes page.