Rinse and halve peppers, remove seeds and ribs and cut into thin strips. Peel radish. Rinse and trim zucchini. Wipe mushrooms clean. Cut or shave zucchini and mushrooms into very thin slices. Divide vegetables among four plates. To make dressing, whisk vinegar with mustard and season with salt and pepper. Whisk in oil. Drizzle dressing over vegetables. Thinly shave Parmesan over vegetables and sprinkle with pumpkin seeds. Garnish with basil leaves.