Add olive oil to a large cast iron skillet over medium heat and sauté onions until browned and caramelized, about 7 minutes. Remove to a bowl and set aside.
In the same cooking pan for taste, cook TWR 100% Grass-Fed Burger Blends to your liking. For Medium-well, about 5 minutes on each side.
While onions & burgers are cooking, prepare homemade ketchup – add all ingredients into a bowl and whisk until fully combined. Add more water as needed to reach desired consistency.
Cut the head of lettuce in half and peel the outside layers from the core – about 5 layers will create a good “bun”.
Place cooked burger blend, brie, tomato, sautéed onion on leaves of lettuce and carefully wrap the lettuce around. Wrap entire burger in parchment paper to serve.
Top burger with homemade MCT ketchup or Primal Kitchen Paleo Ketchup.
