Beef n spinach casserole

Ingredients

• 1 libra. ground beef, browned and drained
• 1 big onion
• 3 cloves of garlic
• 3 cups packed fresh baby spinach
• 4 ounces cream cheese, at room temperature
• 1 egg, at room temperature
• 350 g whole wheat pasta
• 3 cups marble cheese, shredded