Heartwarming Leek & Butter Bean Cheese Pies - Yummy Gusto

Ingredients

• Olive oil
• 3 leeks, washed and cut into rounds
• 100 g unsalted butter
• 2 garlic cloves, finely chopped
• 1 tsp English mustard powder
• 85 g plain flour
• 750 ml milk
• 125 g cheddar cheese, shredded
• 400 g jar of butter beans, washed and drained
• Salt and freshly ground black pepper, as needed
• 3 x 500 g packs of ready-made puff pastry
• 1 egg, whisked
• Mash
• Gravy
• Greens