Ingredients
Gratin
- A bag of potatoes
- 2 large leeks
- 2 shallots
- 2 cloves garlic
- 250ml double cream
- 100ml whole milk
- 1 tsp Dijon mustard
- Thyme
- 1 bay leaf
- Gruyère
- Parmesan
- Butter
- Salt and black pepper
To finish
- Chives
- Lemon zest
- Good olive oil
Method
1. Cook the leeks
Slice the leeks into thick rounds.
Gently cook them with the shallots in butter for 15 minutes until completely soft and sweet.
Add the garlic for the final minute.
2. Infuse the cream
Warm together:
- cream
- milk
- thyme
- bay leaf
- Dijon
- Salt & pepper
Leave to infuse for 10 minutes, then remove the herbs.
This is a tiny step, but it gives the whole dish a more rounded flavour. Similar techniques are used in classic French potato gratins.
3. Assemble
Slice the potatoes thinly.
Layer:
Repeat until finished.
Pour over the warm cream.
Finish with:
- remaining Gruyère
- Parmesan
- plenty of black pepper
Bake at 170°C for around 75 minutes until bubbling and deeply golden.
Rest for 15 minutes before serving.
Finish
Scatter over:
- chopped chives
- a little lemon zest
- a tiny drizzle of good olive oil