Pastitsio

Ingredients

• 1 1/2 lb. ground beef
• 1 c. onion, chopped
• 1 (16 oz.) can tomatoes, crushed
• 1 (6 oz.) can tomato paste
• 1 tsp. salt
• 1/4 tsp. dried crushed thyme leaves
• 1 (7 oz.) box elbow macaroni
• 4 slightly beaten egg whites
• 1/2 c. Velveeta, cubed
• 1/2 c. butter
• 1/2 c. flour
• 1 tsp. salt
• 1/4 tsp. cinnamon
• 4 c. milk
• 4 slightly beaten egg yolks