Culinary Notes
The Rancidity Warning (Crucial Rule): Because the nuts have been pulverised, the massive surface area of their delicate natural oils is entirely exposed to oxygen. If left sitting in a warm pantry cupboard, they will rapidly oxidise and turn aggressively rancid, instantly ruining your bake with a bitter, soapy flavour. They absolutely demand storage in an airtight container in the fridge or, ideally, the freezer to lock the oils into a stable state.
The Structural Reality: You cannot arbitrarily substitute ground almonds 1:1 for wheat flour in a standard sponge cake recipe. Because they possess absolutely zero gluten to trap carbon dioxide, cakes baked heavily with almonds rely entirely on mechanically whipped egg whites (like a classic financier or dacquoise) for their physical rise. Without aerated eggs, you will bake a completely flat, oily brick.
The Moisture Retention: The massive fat content acts as a formidable internal moisture barrier. An almond-heavy sponge will physically resist staling for days longer than a standard wheat cake, making it the absolute superior choice for dense, syrup-soaked desserts (like Middle Eastern citrus cakes) where the crumb must hold heavy liquid without disintegrating into mush.
Blanched vs. Unblanched: Standard ground almonds in the UK are typically blanched (the dark skins are completely removed before grinding). This yields the pale, pristine, and elegant flour required for perfect macarons. Unblanched almond meal contains the crushed skins, which will introduce a heavier, distinctly earthy flavour and a highly speckled, rustic appearance to your pastry.
