1tablespoon finely grated orange or lemon rind (optional)
Crunchy, flaky sea salt
Place almond meal, flour, sugar and salt in a food processor and pulse until blended. Add butter and pulse until mixture is grainy. Add rind if using, and pulse again. Turn dough out onto a work surface and shape into a disc. Wrap in plastic and refrigerate at least 30 minutes.
Preheat oven to 350F. Line 2 baking sheets with parchment paper.
Remove dough from the refrigerator, place on a lightly floured board and knead until soft. Roll to about 1/8 inch thick. Cut into shapes using cookie cutters. Place on prepared pans. Gather up dough scraps and roll out again, cutting out more crackers until all the dough is used.
Use a fork to press holes in the center of each cracker to allow steam to escape from the dough while baking. Beat egg yolk and water together. Brush lightly on crackers. Sprinkle sea salt lightly over all. Bake 12 to 15 minutes, until golden brown and crispy. Let crackers cool completely before storing.