Preheat oven to 400F (or preheat grill to medium). Place each tilapia filet on a piece of tinfoil large enough to fold and enclose tightly. Season each filet with salt and pepper. Divide remaining ingredients by four. Top tilapia filets with garlic, then butter and lemon slices. Add asparagus and tomatoes to packets, then seal packets tightly (see video for demonstration). Place packets on grill or on a baking sheet in the oven. Bake 10 minutes or until tilapia is cooked through and flakes easily with a fork. Serve in foil packets or remove and place on serving plates. Serve immediately.