Preheat oven to 400. Drain tofu, cut into 8 slices. Whisk together vinegar, oil and salt & pepper. Place tofu in baking dish and pour mixture over it. Allow to marinate for 15-30 mins. Pour off most of the marinade, and bake in the oven for 20 minutes or until browned on top (check often, this usually takes 30 minutes, but you don't want to let it burn.)
Whisk sauce ingredients, except mustard, together in a sauce pan over medium heat. Stir often to prevent sauce from burning on the bottom of the pan. Wait until sauce thickens then add mustard and simmer on low for a few minutes.
Toast muffins, layer with tofu, veggie bacon and top with sauce.