Creamy pancetta, Brie and mushroom croissants

25g butter, 70g cubed smoked pancetta, 1 finely sliced garlic clove, 250g halved chestnut mushrooms, 100ml dry white wine, 75ml double cream, the leaves of a few fresh thyme sprigs, 2 all-butter croissants, 100g bite-size pieces of ripe Brie

Melt 25g butter in a frying pan over a medium heat. Add 70g cubed smoked pancetta and cook for 3-4 minutes, until golden. Add 1 finely sliced garlic clove and 250g halved chestnut mushrooms, increase the heat and cook for 5-6 minutes, stirring occasionally, until just softened. Add 100ml dry white wine and bubble for a few minutes until evaporated. Reduce the heat, stir in 75ml double cream and the leaves of a few fresh thyme sprigs. Simmer for a few minutes until thickened. Season to taste. 

Meanwhile, preheat the grill to high. Split 2 all-butter croissants. Put on a baking tray, cut side up, and grill for 1 minute, until toasted. Set the tops aside. Spoon the creamy mushrooms onto each base, scatter with 100g bite-size pieces of ripe Brie, and grill for a further 2 minutes, until the Brie is melting. 

Assemble the croissants again and serve hot, scattered with extra fresh thyme sprigs.