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)