Cook the pasta al dente (it should have a little bite to it but be cooked through).
Heat clarified butter or oil in a large frying pan over high heat. Cook the shrimp, preferably in two batches, first for 2-3 minutes on one side, until golden, then turn them over and cook for about 30 seconds on the other side or until done. Sprinkle with salt and pepper to taste, stir and transfer to a plate. Shrimp only need to change their color from gray to pink, if cooked for too long will be tough and rubbery. If you don’t have clarified butter, you can fry the shrimp in a small amount of frying oil and add a tablespoon of butter at the end of cooking time (so that the butter won't burn).
Cut the zucchini lengthwise in half, then into ¼ inch (½ cm) slices. Add to the pan, cook for about 3-5 minutes, stirring occasionally, until browned, tender, but still crunchy.
Add lemon juice to the pan, season with salt and pepper, scrape with a spatula all the browned bits from the bottom of the pan.
Remove the pan from the heat, add the cooked pasta, shrimps, cut in half tomatoes and basil pesto.
Stir everything together, season with salt and pepper to taste. Serve sprinkled with basil leaves and optionally grated Parmesan cheese.
Enjoy!