Put the sliced garlic into the cold oil in a small deep saucepan. Cold oil, garlic already in.

Set it over low heat. Fine bubbles will start streaming from the edges of the slices after a few minutes.

Let it bubble gently for 10 to 15 minutes, until the slices turn from ivory to a rich toasted amber and curl slightly at the rims.

Take the pan off the heat before you add the chilli. The residual heat is more than enough to bloom the flakes, and ripping-hot oil scorches them.

Stir the chilli flakes in and let the whole thing cool in the pan before jarring.