Make the dough: in a bowl, rub the cold butter into the flour and salt with your fingertips until sandy. Add the egg and bring together quickly into a ball, without overworking. Add ice water only if the dough is too dry. Shape into a disc, wrap, and chill 30 minutes.

Preheat the oven to 350°F. Roll out the dough and line a 9-inch tart pan. Prick the base with a fork.

Blind-bake: cover the base with parchment paper and pie weights (or dried beans), then bake 10 minutes. Remove the paper and weights and bake 5 more minutes to dry the base. This step is what prevents a soggy bottom, the most common mistake on this recipe.

Meanwhile, dry-fry the bacon lardons in a skillet with no added fat until golden and rendered. Drain on paper towel.

Whisk the eggs, cream, and milk with the nutmeg and pepper. Salt lightly, the lardons are already salty.

Scatter the lardons over the pre-baked crust, then pour in the egg custard.

Bake 35 to 40 minutes, until set and golden. Rest 10 minutes before slicing.

Make the same dough and chill 30 minutes.

Roll out the dough and line 6 to 8 mini tart tins or ramekins that fit your air fryer basket. Prick the base of each.

Blind-bake in the air fryer at 325°F for 5 minutes (parchment paper and pie weights, as above).

Divide the lardons and egg custard among the pre-baked shells, not filling to the brim.

Air fry at 325°F for 12 to 15 minutes, until set in the center.

Cool 5 minutes before unmolding. They keep 3 days refrigerated or 2 months frozen, great for packing lunches and reheating 3 to 4 minutes in the air fryer or 1 minute in the microwave.