Combine fatback and bacon in a heavy pot over low heat. Render slowly, stirring occasionally, 15–20 minutes until the fat has melted and the bits are golden.

Add onion and garlic, cooking 5 more minutes until softened.

Stir in bay leaf, marjoram, salt, and pepper.

Remove bay leaf, then transfer everything to a container and chill until firm, at least 2 hours.

For the crisps: mix almond flour, egg, and salt into a dough, roll thin between parchment, and cut into small rounds.

Bake crisps at 325°F (165°C) for 10–12 minutes until golden. Cool completely.

Spread chilled smalec thickly on the crisps just before serving.