Lay each mushroom flat on a board and holding your hand flat on top cut through from one side to the other. Do this twice so you have three slices which when put back together form a mushroom again
Slice the tomatoes about a 1/4 " thick
Pick the basil into leaves
Method
Line a large baking tray with greaseproof paper.
Place the bottom slice (stalk) of each mushroom on the paper, top with slices from half a tomato, a basil leaf, sprinkle with pine nuts and top with Sheese slice.
Add the middle slice and repeat. Finally top with the last mushroom slice and bake in a pre-heated oven for 20-25 minutes. Serve with a crispy salad.