Bring the water to a boil, then soak the whole almonds in the boiling water for 1 to 2 minutes.

Drain the almonds, then slip off and discard the skins.

Spread the peeled almonds in a single layer on the baking sheet, then dry them in the oven at 100°C / 212°F until completely dry, about 60 to 90 minutes.

Cool the dried almonds completely, then transfer a small batch to the blender.

Pulse the almonds in short bursts until finely ground, stopping before they release oil and turn into almond butter.

Sift the ground almonds through the fine-mesh sieve, then re-blend any coarse pieces in small batches.

Transfer the fine, fully cooled almond flour to an airtight jar, then seal it tightly.