Prepare the ingredients: Slice the shallot and fennel, then mince the garlic. Cut the cherry tomatoes in half.
Sauté the aromatics: Melt butter in a 12-inch skillet over medium heat. Add the shallot, fennel, and garlic, stirring frequently until softened, about 4 minutes.
Cook the tomatoes: Stir in the halved tomatoes, saffron, salt, and pepper. Let the mixture cook for 3 to 4 minutes, stirring occasionally, until the tomatoes start releasing their juices.
Poach the fish: Place the fish fillets directly onto the simmering tomatoes. Lightly press them into the sauce, then season the fish with a little extra salt and pepper. Reduce heat to medium-low, cover the skillet, and let the fish cook for 7 to 10 minutes, or until it flakes easily with a fork.
Warm the pita: While the fish is cooking, heat the pita bread under a broiler or in a toaster oven for a few minutes. Optionally, brush with olive oil before warming.
Serve: Divide the fish and tomato mixture onto four plates, and serve with pita on the side to scoop up the sauce.