Core the tomatoes and cut into bite-sized pieces. You shouldn`t skip the pitting, otherwise the gratin will be very watery.
Grease a baking dish with a little olive oil and add the tomato pieces. Cut the spring onions into rings and finely chop the garlic. Put on the tomatoes.
Add the pesto too. Just take your favorite pesto. In my case it is the delicious rocket pesto from the head chef user motte1073
Then add the grated cheese (put a handful aside) and mix everything well. Season to taste with the spices. Now pour the rest of the cheese over the gratin and put it in the oven. There it is baked for about 20 minutes until the cheese turns nice and brown on the surface.
We like to eat this gratin as a fruity low-carb side dish to a nice piece of grilled meat - but of course you can vary the quantities and conjure up a main course by simply serving a delicious bread.