Single serve Apple Crumble you can make in the microwave

This single-serve apple crumble uses six simple ingredients and the microwave. Pick a good baking apple, add a pinch of cinnamon, and top it with a quick oat crumble. In just a few minutes, you get tender apples in a light cinnamon sauce with a crisp, buttery topping. Serve it warm and call it dessert.

A small white dish of apple crisp topped with a scoop of vanilla ice cream and caramel sauce, next to a green apple, cinnamon sticks, and a green cloth.

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Single Serve Apple Crisp. Photo credit: One Hot Oven.

Sometimes you want something sweet but don’t want to bake a whole pan. That’s where this recipe shines. It makes just one serving and cooks right in a mug or ramekin. No oven, no leftovers, and very little cleanup.

Many readers ask for smaller recipes that don’t feed a crowd. This one is made for those nights when you want a quick treat after dinner, a late-night snack, or a way to use up a single apple sitting on the counter.

And if you’re standing in the kitchen wondering if something this simple will really work, it will. The microwave softens the apples quickly and gives you that cozy apple crumble flavor without turning on the oven.

Why This Quick Crumble Works

The microwave softens the apples first, so they start releasing their juices. That gives you a light sauce before the crumble topping even goes on.

Then the oat topping cooks right on top of the fruit. The butter melts into the oats, flour, and brown sugar, which helps the crumble set and gives it that classic texture.

The whole thing takes only a few minutes, which makes it one of the easiest desserts you can make.

Ingredients

You only need a few pantry staples.

A green apple, flour, old-fashioned oats, brown sugar, butter, and cinnamon are arranged in bowls on a white surface for apple crisp in a mug.

Apple
Use a firm apple that holds its shape while cooking. I often reach for Granny Smith because the tart flavor balances the brown sugar. Fuji, Gala, or Jonagold work well, too.

Old-fashioned oats
These give the crumble texture and structure. I skip quick oats because they soften too much.

Brown sugar
Adds sweetness and helps create that classic crumble flavor.

Flour
Helps hold the topping together, forming small clumps.

Butter
Butter goes in both the apples and the crumble topping. It adds flavor and helps the topping set as it cooks.

Cinnamon
A small pinch adds warm spice and brings everything together.

Equipment

You don’t need much for this recipe.

Use a 12 to 16-ounce microwave-safe mug or ramekin. If you’re unsure about the size, fill it with water and pour the water into a measuring cup to check the capacity.

You’ll also want a small bowl and a fork for mixing the crumble topping.

How to Make a Single-Serve Apple Crumble

Prep the apple

Core the apple and cut it into small cubes. You can peel it if you like softer fruit, but leaving the peel on works fine too.

Start the filling

Place the apple cubes and a small pat of butter in your mug or ramekin.

Microwave for 30 seconds. Stir, then microwave another 30 seconds. Sprinkle the apples with cinnamon and stir again. The apples will soften and settle as they cook.

Make the crumble topping

In a small bowl, combine old-fashioned oats, flour, brown sugar, and a pinch of cinnamon.

Add softened butter and mash it into the mixture with a fork until it looks sandy with small clumps.

Finish the crumble

Spoon the topping over the warm apples.

Microwave on high for about 2 minutes, just until the apples are tender and the topping has set.

Be careful when removing the mug from the microwave. It will be very hot.

Let the crumble sit for a minute or two before eating.

Serving Ideas

This crumble is great on its own, but a topping makes it even better.

Try adding:

a scoop of vanilla ice cream
whipped cream
a drizzle of caramel sauce

The ice cream melts into the warm apples and creates a quick sauce.

A white bowl filled with a single serve apple crisp topped with a scoop of vanilla ice cream and a drizzle of sauce, with a spoon inside.

Variations

Once you’ve made the basic version, it’s easy to change things up.

Add nuts
Chopped pecans, walnuts, or almonds bring extra crunch.

Add dried fruit
Raisins or dried cranberries mix nicely with the apples.

Change the spices
Along with cinnamon, try a pinch of nutmeg, ginger, cloves, or cardamom.

Make the filling thicker
If you like a more saucy filling, stir a tiny pinch of cornstarch and about ½ teaspoon lemon juice into the apples before microwaving.

Can You Bake It Instead?

Yes, you can bake this crumble if you prefer.

Assemble everything in a small ramekin and bake at 350°F for about 18 to 22 minutes. The topping should be lightly golden and the apples bubbling.

A toaster oven works well too and usually takes about the same time.

Storage

This crumble is best eaten right after cooking while it’s still warm.

If you have leftovers, cover the ramekin and store it in the refrigerator. Reheat in the microwave the next day until warmed through.

Quick Questions

How long should the apples cook first?
Microwave the apples for about 1 minute before adding the crumble topping.

Can this be made gluten-free?
Yes. Use certified gluten-free oats and a 1-to-1 gluten-free flour.

Can I skip the oats?
You can replace the oats with finely chopped nuts and add a little extra flour to help hold the topping together.

If you’re ready to make it, the full recipe with exact measurements is just below.

Baker’s Note

I’ve made this little mug crumble more times than I can count when I want a quick dessert without turning on the oven. The microwave softens the apples quickly and the oat topping sets just enough to give you that classic crumble texture. If your apple is extra juicy, let the crumble sit for a minute before eating so the sauce thickens slightly.