Philly Cheesesteak Mac and Cheese

Ingredients

• 2 cups uncooked small pasta shells
• 1 tablespoon oil
• Salt and black pepper
• 1 pound thinly sliced sirloin
• 3 tablespoons butter
• 1 small diced yellow onion
• 1 diced green bell pepper
• 8 ounces sliced white mushrooms
• 2 minced garlic cloves
• 1 teaspoon salt
• 1/2 teaspoon ground black pepper
• 2 tablespoons all-purpose flour
• 1 cup half-and-half
• 1 cup whole milk
• 2 cups shredded provolone cheese