Heat oven to 300° and melt the butter, then set it aside to cool.
Cut one piece of parchment and one of the wax paper the size of your baking sheet. Spray one side of each with avocado or olive oil.
In a medium bowl combine almond flour with baking powder, ¼ tsp sea salt, ½ tsp rosemary and the garlic powder. Mix well, breaking down the almond flour clumps as you go.
Using the small side of a cheese grater or a zester, grate the aged cheddar until you have ¼ cup shredded cheese. Mix into the almond flour then knead in the egg white and melted butter until fully combined.
Scrape out onto the center of the oiled parchment paper. Lay the oiled wax paper over top of the dough and roll out into until it’s roughly 20cms by 30cms.
It will form an oval but to make a perfect rectangle, just remove the wax paper and trim into a rectangle, using the trimmed dough to fill in the corners.
Form the cracker shapes with a knife, pizza blade or fondant scraper; Don’t cut all the way through. Sprinkle with remaining rosemary and a pinch of sea salt. Use a meat mallet to create the dimpled cracker look, or leave as is.