Channel 4 show Cookery School, fronted by Gizzi Erskine and Richard Corrigan, teaches you how to cook like a pro. This gratin dish makes a lovely family supper
- 250g plain flour, sifted
- 300ml whole milk
- 2 eggs
- 2 tablespoons melted unsalted butter
- 2 tablespoons vegetable oil
- 50g Parmesan cheese, grated
- Mushroom filling
- 75g unsalted butter
- 2 banana shallots, peeled and finely chopped
- 1 garlic clove, peeled and finely chopped
- 1kg button mushrooms, finely chopped
- 2 teaspoons finely chopped thyme leaves
- 2 teaspoons finely chopped flat-leaf parsley
- Bechamel sauce
- 400ml whole milk
- 1 bay leaf
- 8 black peppercorns
- ½ onion, peeled
- 40g unsalted butter
- 20g plain flour, sifted
- ½ teaspoon cayenne pepper
- ½ teaspoon freshly grated nutmeg
- 500g baby spinach leaves
- 1 tablespoon extra virgin olive oil
Preheat the oven to 200°C/fan 180°C/gas 6.
To make the crêpes, sieve the flour into a large bowl and gradually mix in the milk, 300ml of water, eggs and butter, then whisk until smooth.
Heat a medium-sized non-stick frying pan over a medium heat. Once the pan is hot, add a little of the vegetable oil. Then pour in a ladleful of the crêpe batter and swirl the pan to spread out the batter and form a thin crêpe. Cook for 2 minutes, flip the crêpe over using a spatula, fish slice or palette knife and cook for a further minute on the other side. Slide the crêpe out of the pan on to a plate to one side and place a sheet of kitchen paper on top to stop the crêpes from sticking together. Repeat with the rest of the batter, one ladleful at a time and adding a little more oil to the pan between cooking each crêpe, until you end up with a pile of 8 cooked crêpes interleaved with sheets of kitchen paper.
To make the mushroom filling, place the butter in a medium-sized sauté pan over a medium heat. Once the butter has melted, add the shallots and cook for 2 minutes until they are soft, then add the garlic, mushrooms and thyme and cook for a further 8–10 minutes, until the moisture from the mushrooms has evaporated. Remove the pan from the heat, season with salt and pepper and sprinkle on the chopped parsley. Set aside.
To make the béchamel sauce, place the milk, bay leaf, peppercorns and onion in a medium-sized saucepan and warm over a low heat but do not let the milk boil. In a separate medium-sized saucepan, melt the butter over a medium heat then add the flour to make a roux. Cook, stirring, for 2–3 minutes.
Strain the warmed milk, discarding the aromatics, and gradually pour the milk into the roux, whisking all the time. Cook for a further 5 minutes until you have a smooth, thickened béchamel sauce, then season with salt, cayenne pepper and nutmeg. Take 2 tablespoons of the sauce and mix into the mushroom filling to bind that together.
On a clean work surface, lay 2 crêpes overlapping one another to give a large surface area and spread a quarter of the mushroom filling evenly over the crêpes. Taking the end nearest to you, roll up into a Swiss roll shape. Cut the roll into 2cm-thick pieces. Repeat with the remaining 6 crêpes and the rest of the filling.
Heat a medium-sized frying pan over a low to medium heat, throw in the baby spinach and drizzle over the extra virgin olive oil. Cook for 2 minutes until the spinach leaves have wilted.
Place the wilted spinach in the bottom of 4 x 5 inch/13cm round or oval individual gratin dishes, or use one large dish. Pour a little béchamel sauce over the top and then place a quarter of the slices of filled crêpe roll on top, overlapping the slices slightly. Pour the remaining béchamel sauce over the top and sprinkle on the grated Parmesan.
Place the 4 gratin dishes on a baking tray and put in the preheated oven for 8–10 minutes until the gratins are golden brown on top.
Top tip for making Mushroom crepe gratin
There are four elements that make up this recipe: the mushrooms, the crêpes, the sauce and the garnish. If you break it down into these components, you won’t go too far wrong.