1. To prepare the marmalade, place onions in a large, heavy saucepan and add chicken stock. Cover and cook over medium heat for 15 minutes. Add thyme leaves and garlic powder, and cook, uncovered, for about 45 minutes or until onions start to color and liquid is almost evaporated. Add cream and cook until mixture thickens. Add vinegar and cook for 2 minutes. Remove from heat and set aside.

2. Preheat the oven to 350 °F.

3. Place Catfish fillets on a flat surface. Season with salt and pepper. Spread 1 tablespoon of the Onion marmalade over each fillet. Starting with the smaller tail end, tightly roll fillets and secure with toothpicks. Arrange rolled fillets in a shallow baking dish several inches apart. Top each with 1 tablespoon of marmalade.

4. Bake for 10 minutes or until flakes easily when tested with a fork. Remove from oven and let sit for 5 minutes. Place 3 tablespoons of marmalade on each warmed serving plate and top with the cooked fillets. Remove toothpicks before serving.