300g broccoli, chopped into florets
350g cauliflower, chopped into florets
220g Brussels sprouts, quartered
1 tsp olive oil
2 onions, sliced
120ml cream, at room temperature
250ml milk, at room temperature
½ tbsp Dijon mustard
120g Gruyère, grated
120g Gouda, grated
Salt and black pepper
For the crumb topping:
- Preheat the oven to 180˚C/160˚C fan/gas mark 4.
- Bring a large pot of water to the boil. Add the broccoli, cauliflower and Brussels sprouts and cook for 2-3 minutes until the broccoli turns vibrantly green.
- Transfer the vegetables to a large bowl of ice water for two minutes, then drain and place in a large casserole dish.
- Heat the olive oil in a saucepan over a medium-high heat and cook the onions for 4-5 minutes until golden and soft, stirring occasionally.
- Reduce the heat to medium-low heat and add the butter. Once melted, gradually mix in the flour, whisking constantly. Continue cooking and whisking for 1-2 minutes.
- Gradually add the cream and milk, whisking constantly until the sauce thickens.
- Remove the saucepan from the heat and stir in the mustard, half of each of the cheeses and some salt and black pepper to taste.
- Pour the sauce over the vegetables, then top with the remaining cheese.
- Melt the butter for the topping in a bowl and stir in the breadcrumbs until combined, then sprinkle over the casserole.
- Bake for 20-25 minutes until golden on top and bubbling around the edges.
Per Serving 323kcals, 20.4g fat (11.8g saturated), 22.3g carbs, 5.7g sugars, 15g protein, 4.2g fibre, 0.276g sodium