Mary Berry Cheese and Onion Pie is made with plain flour, unsalted butter, free-range eggs, parmesan cheese, potato, onions, whole milk, double cream, mature cheddar cheese, English mustard, and cayenne pepper. This tasty Mary Berry Cheese and Onion Pie recipe creates a hearty dinner that takes about 2 hours and 10 minutes to prepare and can serve up to 4 people.