1 Rinse and pat dry the sole filets. Rinse and pat dry the tomatoes, then cut in half or quarters, depending on size. Rinse the asparagus, peel the lower third with a potato peeler and remove the woody ends. Blanche in boiling salted water for 2 minutes, then drain, rinse with cold water and cut in half.
2 Rinse lemon in hot water, wipe dry and remove zest using a citrus zester, then finely chop the zest. Slice the lemon, then halve the slices. Peel and finely chop the garlic, mix with the chopped lemon zest and evenly sprinkle on 4 large pieces of aluminum foil. Place 1 tsp butter in each piece of foil, then add the fish filets. Arrange tomatoes, asparagus and lemon slices on top.
3 Drizzle with oil and sprinkle dill on top. Season with salt and pepper. Seal the foil packets up tightly. Cook on a hot grill (or under the broiler, watching carefully) for about 10 minutes. Remove from heat, let cool slightly, then arrange on serving plates. Serve immediately.