Turn the oven on to 180°C.
Remove the stems from the mushrooms and chop them finely.
Put the mushroom on a lightly oiled baking tray and bake them for 10 minutes.
Meanwhile finely chop the pepper, garlic, onion, chilli and sun-dried tomatoes.
Heat the oil in a frying pan and gently sauté the pepper, onion and chilli for 8-10 minutes, then stir in the sun-dried tomatoes and basil. Season with salt & pepper to taste.
Drain, then cut the mozzarella ball into 4 slices.
Take the mushrooms out of the oven, stuff them with the mixture then cover with the mozzarella.
Put the tray back into the oven and bake for another 8-10 minutes until the cheese has melted.