1 lb. ground beef
1/2 medium onion, chopped (about 1/2 C.)
1/2 C. celery, chopped (about 1 rib of celery)
1/2 C. green or red pepper, chopped (about 1/2 large pepper)
1/4 C. water
1/2 C. tomato ketchup
1 T. prepared mustard
1 tsp. sugar
5 whole wheat buns
Combine ground beef, onion, celery, and pepper in a medium skillet. Add water. Cook over medium low heat for 15 minutes. Stir as needed. Cook until beef mixture reaches at least 160°.
Put ground beef mixture in a colander set over a bowl. Pat mixture with paper towels and rinse with warm water to remove fat. Return to skillet. Add ketchup, mustard, and sugar. Heat 5-10 minutes on low heat.
Toast buns in an oven broiler, toaster oven or skillet. To use a skillet, spread buns with margarine and place face side down in skillet. Cook over medium heat 1-2 minutes. Prepare sandwiches by putting 1/2 C. of meat mixture on bottom of each bun and cover with top of bun.