Preheat the oven to 350F.

Bring a pot of water to a boil. Parboil the plums for 3 minutes.

Plunge them into a bowl of cold water and peel off the skins.

Slice thinly.

Flatten the chicken breasts out with a mallet or rolling pin.

Season on both sides with salt and pepper.

Add a layer of plum slices on top, then arrange the cheese slices.

Roll up the chicken rolls tightly and fix each with toothpicks.

Briefly blitz walnuts in a blender.

Whisk the walnuts together with the panko breadcrumbs.

Beat the eggs in a separate bowl.

Roll each piece in egg and then coat them with the breadcrumbs mixture.

Place in the baking dish.

Bake for 30 minutes.

Remove toothpicks and serve.