Leek onions clean, wash, lengthwise halve and in approx. 3 cm long pieces cut. Wash the zucchini and cut into strips. Let a grill pan get very hot, brush with oil and grill vegetables on it. Drain on kitchen paper. Wash, halve and slice the tomatoes.
Drain mozzarella and cut into slices and halves. Toast bread, remove crusts, cut in half and spread one half with pesto. Cover toast with tomatoes, mozzarella and grilled vegetables. Season with salt and pepper and garnish with parsley and thyme