Preheat oven to 450°. Stir together first 3 ingredients; let stand 5 minutes.
Meanwhile, sauté onion in hot oil in a medium-size nonstick skillet over medium heat 5 minutes or just until tender.
Stir together bread mixture, onion, ground beef, next 5 ingredients, and 2 Tbsp. relish just until blended.
Shape into 8 loaves (about 1/2 cup each); place in cups of a lightly greased 8-cup mini loaf pan. (Each cup will be about 3 1/2 x 2 1/2 inches. Or arrange on a lightly greased wire rack in a foil-lined jelly-roll pan.)
Bake at 450° for 25 to 30 minutes or until a meat thermometer registers 155°, brushing with 1/3 cup relish during last 10 minutes of baking. Remove from oven; let stand 5 minutes. Serve with remaining relish.
We loved this too! What a delicious twist on a traditional favorite! The only pepper relish we could find was Ragin' Cajun Fixin's Spicy Sweet Jalapeno Relish. It's become a staple in the house now and the meatloaves recipe added to favorites.