Lay a baking sheet sized piece of parchment paper flat on a work surface and lightly dust with almond flour. Have a second sheet of the same size nearby.
Place almond flour, kosher salt and parmesan cheese into the bowl of a food processor; pulse a few times to combine. Sprinkle in cubes of butter and pulse until the mixture resembles a coarse meal. Drizzle cream or half and half over mixture and process until dough just comes together, about 5 seconds.
Turn dough out onto dusted sheet of parchment paper (dough will be sticky). Gently pat dough into a ½-inch thick rectangle and dust generously with almond flour. Place second sheet of parchment paper over the dough and, with a rolling pin, roll into an ⅛-inch thick loose rectangle. Carefully remove top layer of parchment (if it starts to stick, use a rubber spatula to gently separate the parchment from the dough). With a pizza cutter or sharp knife, cut dough into 1 ½-inch square crackers, trimming outside edge. (Don't try to separate crackers at this point, the dough is too sticky.)
Transfer dough on parchment directly to baking sheet. Bake 12 minutes and remove from oven.
Reduce oven temperature to 250˚F and crack oven door open to allow heat to escape while you divide crackers.
Use pizza cutter to cut dough into crackers, following the lines you scored before baking. With a thin, small spatula gently separate each cracker so that it has a little bit of space all around.
Bake 15-20 minutes more, until light golden brown and crisp, rotating baking sheet every 5 minutes. (recipe note #1) Transfer baking sheet to wire cooling rack. Let crackers cool completely in baking sheet (they'll crisp more as they cool). Serve or store in an airtight container at room temperature for up to 3 days or freeze for up to 1 month.
Cooking for an extended time at a lower temperature gives these crackers their flaky, crisp texture.