Crock Pot Southwestern Beef Wraps

1 medium onion, cut into 1" wedges
1 boneless beef chuck roast (2 1/2 lbs) well trimmed and cut into 6 pieces
1 tsp. chili powder
1 tsp. cumin
1 tsp. garlic powder
3/4 tsp. salt
1 green pepper, cut into 1/2" pieces
1 can diced tomatoes iwth mild green chilies, undreained
1-2 T. chopped fresh cilantro
24 flour tortillas (6"), warmed
sour cream
salsa

Place onion in slow cooker. Place pieces of beef over onion. In a small bowl, combine chili powder, cumin, garlic powder and salt; sprinkle half over beef. Turn beef over and sprinkle with remaining seasoning mixture. Top with green pepper, then pour tomatoes over all. Cover and cook on high 5 hours or low 9 hours. Remove meat from cooker and shred. Drain liquid from remaining vegetable mixture. Return meat and vegetables to cooker and stir in cilantro. To serve, use slotted spoon to fill warm tortillas with beef mixture. Top with sour cream and salsa if desired.

Makes 2 dozen wraps.