Mum's Cottage Pie

Ingredients (12)

• + 2 large potatoes, peeled and diced add to pantry
• + 2 tablespoons milk add to pantry
• + 1 tablespoon butter add to pantry
• + salt and ground black pepper to taste add to pantry
• + salt and ground black pepper to taste add to pantry
• ✓ 1 tablespoon vegetable oil, or as needed
• + 1 large onion, diced add to pantry
• ✓ ½ pound lean ground beef
• + ⅓ cup dry sherry add to pantry
• + 1 dash Worcestershire sauce add to pantry
• + 1 ½ teaspoons all-purpose flour add to pantry
• + ½ cup grated Parmesan cheese add to pantry