In a small bowl, combine butter, garlic, and parsley. Set aside.
In a glass bowl, combine olive oil, garlic, parsley, tomato paste, basil, lemon juice, salt and pepper. Add the shrimp and marinate for at least 20 minutes or up to 1 hour.
Preheat the grill to medium heat (375°F).
Thread the shrimp onto skewers and grill for 2-3 minutes per side or just until the shrimp are opaque. Remove from skewers and place in a serving bowl.
If needed, warm the garlic butter in the microwave for a few seconds to melt. Drizzle the garlic butter over the shrimp and serve warm with lemon wedges if desired.
