Coulis is just a fancy term for a thick pur?E or sauce. Here, its a vibrant green pur?E with a minty finish, and it makes a delicious match for mild roasted halibut. Roasted tomato wedges preheat oven to 400f (200c). Slice plum tomatoes into thick wedges. Brush with olive oil. Roast on a foil-lined baking.