Sprinkle pork with salt and pepper. Cook, in batches, in hot oil in a large skillet over medium-high heat 3 minutes on each side or until done. Transfer pork to a wire rack in a jelly-roll pan, and keep warm in a 200° oven.
Add shallots and thyme to skillet; sauté 1 minute or until tender. Stir in wine and pepper jelly until smooth. Stir in peach and tomato, and cook, stirring often, 2 to 3 minutes or until thoroughly heated. Add salt and pepper to taste. Pour sauce over pork, and serve immediately with grits.