Beef Tostada Pie

Ingredients

• 1 lb. ground beef
• 1 large onion, chopped
• 1 clove garlic, finely grated
• 1/2 tsp. oregano leaf, crumbled
• 1 (16 oz.) can whole tomatoes in puree
• 1 (4 oz.) can chopped green chilies (undrained)
• 1 large can refried beans
• 2 c. Cheddar cheese, grated
• 2 Tbsp. all-purpose flour
• 1/2 tsp. cumin, ground
• 1/2 tsp. salt
• 1/8 tsp. pepper
• Doritos chips