Cajun Shrimp and Rice

Name: Cajun Shrimp and Rice
Ingredients: 1 tablespoon unsalted butter; 2 tablespoons extra-virgin olive oil; 3 cloves garlic, minced; 2 teaspoons Cajun seasoning; 1 pound large shrimp, peeled and deveined, tails intact; Kosher salt and freshly ground pepper; 4 plum tomatoes, chopped; 2 bunches scallions, chopped; 3 cups cooked white rice; 3 tablespoons chopped fresh parsley; Lemon wedges, for serving (optional)