Chicken, Cheese and Mustard Pie
A chicken, cheese and mustard pie is a pie built on a mornay style sauce, a white sauce enriched with mature cheddar and sharpened with wholegrain mustard. The cheese goes in off the heat so it melts smoothly instead of splitting, and the mustard keeps the richness in check.
By the chickenpie.net test kitchen · Published 11 September 2026
- Prep
- 30 min
- Cook
- 45 min
- Yield
- 6 servings
Ingredients
- 500g skinless chicken breast, diced
- 1 leek, sliced
- 1 tbsp olive oil
- 30g butter
- 30g plain flour
- 250ml chicken stock
- 150ml whole milk
- 100g mature cheddar, grated
- 1.5 tbsp wholegrain mustard
- 320g ready rolled shortcrust pastry
- 1 egg, beaten, for glazing
Method
Heat the oil in a wide pan, cook the leek for 5 minutes, then add the chicken and cook for 6 minutes until sealed.
Add the butter, let it melt, stir in the flour, and cook for 1 minute.
Gradually add the stock and then the milk, stirring constantly, and simmer for 4 minutes until thick.
Take the pan off the heat and stir in the cheddar and mustard until the cheese melts smoothly, then season with pepper and transfer to a 1.5 litre pie dish to cool for 10 minutes.
Top with the pastry, trim and crimp, cut a steam vent, and brush with beaten egg.
Bake at 190C (375F) for 30 minutes until golden, then rest for 5 minutes before serving.
Worth knowing
- Always add cheese off the heat, boiling a cheese sauce makes it grainy and greasy.
- Buy a block of mature cheddar and grate it yourself, pre grated cheese has anti caking coatings that dull the sauce.
Common questions
Can I use a different cheese?
Yes. Gruyere melts beautifully and adds nuttiness, and red Leicester gives colour with a milder taste. Avoid mozzarella, it goes stringy, and very fresh cheeses, which make the sauce watery.
Is wholegrain mustard essential?
It gives texture and gentle heat, but 2 teaspoons of Dijon works instead. Avoid English mustard at the same quantity, it is much hotter, use half a teaspoon at most.
Why did my cheese sauce split?
It got too hot after the cheese went in. Add the cheese off the heat and, if reheating the filling later, warm it gently. A splash of milk whisked in can bring a slightly split sauce back.