For the pasta casserole, preheat the oven to 175 degrees. Place the uncooked pasta in a baking dish. Slice the tomatoes and zucchini and spread over the pasta.
Cut the feta into small pieces and spread over the tomatoes/zucchini, add olives on top. Heat the vegetable soup with the whipped cream, squeeze in a clove of garlic.
Add thyme, basil and mustard and mix well. Bring everything to the boil and pour into the casserole dish.
Cook the pasta casserole in the preheated oven for about 20-25 minutes. Let it cool a bit before serving, otherwise it will fall apart.