Step 1

To make the pastry, place the oats into a food processor and blitz until floury, with a few small pieces of oat remaining. Add the flour and butter, then pulse until the mixture resembles fine breadcrumbs. Add 2-3 tbsp water and pulse to combine. When the mixture clumps together, knead briefly, then shape into a flat disc, wrap and chill in the fridge for at least 30 minutes, or until required (the pastry will keep for up to 2 days at this stage).

Step 2

Preheat the oven to 200ºC, gas mark 6. Roll the chilled pastry out on a lightly floured surface, or between 2 pieces of baking parchment, to a 0.5cm thickness and large enough to line a deep 18-20cm round fluted tart tin. Using a small piece of pastry, press the sides in firmly. Roll the rolling pin across the top of the tin to cut off excess pastry, prick the base with a fork, then chill for 15 minutes more.

Step 3

Line the pastry case with a sheet of baking parchment (scrunching the paper first helps it go all the way to the edges). Fill to the top with baking beans. Bake for 15 minutes, then remove the beans and paper and bake for 10 minutes more until the base is crisp.

Step 4

Reduce the oven to 180°C, gas mark 4. In a large jug, beat together the 2 whole eggs, 1 egg yolk and double cream until smooth. Season well with black pepper and a few fine gratings of nutmeg, then set aside.

Step 5

Heat the oil in a small frying pan over a medium heat. Add the lardons and fry for 5-6 minutes until crisp. Remove from the pan using a slotted spoon and arrange over the pastry case.

Step 6

Lower the heat under the pan to medium and fry the shallot in the bacon fat until softened, around 8-10 minutes, then add to the pastry case. Scatter ½ the Gruyère over the shallots and bacon, then pour in the egg mixture and fill to the top of the case. Sprinkle the remaining cheese over the top.

Step 7

Bake for 20-25 minutes, until the quiche is golden on top and the filling is set and slightly puffed up. Allow to cool slightly, then enjoy warm or at room temperature with salad.