500g brussels sprouts, bases trimmed, cut in half
2 tsp olive oil
1 onion, finely sliced into half moons
180g speck (or bacon), cut into lardons
1 granny smith apple, peeled and cut into 1.5cm cubes
180mL white wine
1 tbsp dijon mustard
45g (¾ cup) panko breadcrumbs
Zest of 1 lemon
75g cheddar or Gruyère cheese, grated
½ tsp freshly grated nutmeg
Preheat the oven to 200°C.
Bring a large saucepan of water to the boil, add the brussels sprouts and cook for 10 minutes until just tender. Drain and set aside.
Heat the oil in a frying pan over medium heat, add the onion, speck (or bacon) and a touch of salt and sauté for 5–8 minutes until the onion and speck are golden brown. Now add the apple and white wine and stir to deglaze the pan. Cook until reduced by half, about four minutes, then stir in the mustard and cream. Bring to the boil, reduce the heat to low and simmer for five minutes until the sauce coats the back of a spoon.
Arrange the brussels sprouts in a 1.5L baking dish and pour over the cream mixture.
Combine the breadcrumbs, lemon zest, cheese and nutmeg in a bowl. Evenly spread over the gratin and bake in the oven for 25 minutes until the top is golden and crunchy.