Melt butter in a small (microwave safe!) bowl until just melted, but not piping hot. Set aside to cool while you mix the flours.
Add the almond flour, xanthan gum, baking powder and salt to a medium bowl and whisk thoroughly. Pour in the butter and mix until evenly distributed (I just use my hands!). Add in your lightly whisked egg (1/2 egg is roughly 1 1/2 tablespoons or 25g) and continue to knead until it forms into a ball. Cover in cling film and place in the freezer for 5 minutes to solidify the butter.
Roll out the dough between two sheets of parchment paper, sprinkle seasoning and lightly roll again to press it in. Trim to desired cracker size and separate gently. The dough is fragile, so I separate the pieces by running a knife underneath.
For medium crackers, cook on high in the parchment paper for 20 seconds, open the microwave and cook for another 15-20 seconds. The crackers will continue to crisp up as they cool, but I suggest you do a trial with a couple to nail down your time!
Note: cooking times can vary a lot depending on your cracker size and microwave, and I found they cook more evenly in batches of 4-6 (as opposed to the whole batch!) and in two bursts. My microwave is 1000 watts. Also be sure to cook your dough right away, as leaving it in the fridge overnight makes the almond flour harder to crisp up (as it has absorbed the liquid and essentially ‘blanched’).
Note 2: these can be baked too! Just do 8-12 minutes in your oven at 350F/180C until lightly golden (will depend on size and thickness). And to make them extra crisp, feel free to do a double bake biscotti-style (i.e. let them cool, and bake them again for 5 minutes).