Cut off the bottom piece of the apples so they stand up nicely. Remove the core with an apple corer. Cut the apples into 1-inch slices. Coat the apple slices with a little olive oil.

Place a slice of mozzarella between the apple slices and season with a little black pepper. Reconstruct the apple and insert a large toothpick (skewer).

Place the apples in a baking dish. Pour olive oil and balsamic vinegar over them and place the dish in a hot oven at 180 °C for 30 minutes. Sprinkle in the walnuts during the last 10 minutes. They will become deliciously crunchy and full of flavor.

Tip!
You can buy large, thin slices of mozzarella straight from the supermarket. You can also cut the typical mozzarella balls into thin slices, but that's more fiddling.

Tip!
If an apple does not stand up nicely straight in the oven, it sometimes happens that it sags a little. That doesn't pose a problem: when you take the dish out of the oven, remove the stick, push the apple back into the right shape and insert the skewer again.