James Martin served up a tasty lobster thermidor for Mary Berry on Home Comforts at Christmas.

The ingredients are: 1.5kg whole cooked lobster, cut in half lengthways, meat removed, shells cleaned and reserved, 50g butter, 2 shallots, finely chopped, 125ml white wine, 500ml fish stock, 250ml double cream, 1 tsp Dijon mustard, 100g chanterelle mushrooms, cleaned, 2 tbsp roughly chopped flatleaf parsley, squeeze lemon juice, 25g grated Parmesan, 2 free-range egg yolks, 25g fresh breadcrumbs, 4 King Edward potatoes, peeled and cut into matchsticks, vegetable oil, for deep frying and sea salt and freshly ground black pepper.