Vegetable Pot Pie

Dice the onion, carrots and celery, and quarter the mushrooms.

Melt the butter in a large saucepan over medium heat and cook the onion, carrots and celery for 6 minutes until softened.

Add the mushrooms and cook for 5 minutes, stirring, until they release their liquid and start to brown.

Stir in the flour and cook for 1 minute, then gradually whisk in the vegetable stock and milk until smooth.

Simmer for 8 minutes, stirring occasionally, until thickened.

Stir in the sweetcorn, peas, thyme, salt and pepper, then pour the filling into a pie dish.

Preheat the oven to 200°C and drape the puff pastry over the filling, trimming and crimping the edges.

Brush the pastry with beaten egg and bake for 25 minutes until puffed and deep golden.