Process all dry ingredients in a food processor until batter forms a flour.
Add water, cacao butter, lemon zest and vanilla and process until batter starts sticking together and forms a dough.
Roll dough into a ball and place on a piece of parchment paper taped to the counter and dust parchment paper with oat flour .
Flatten out dough and top with a little more oat flour to prevent from sticking.
Place another piece of parchment paper on top and roll out evenly using a rolling pin about 1/4" thick.
Using linzer cookie cutters, cut cookies for bottom and top.
Remove dough away from cookies and repeat process until batter is used.
Leave cookies on the parchment paper and transfer onto a cutting board or tray and set in freezer for 1/2 hour.
Place 1 tsp of jam in middle of the base of a cookie and place top on.
Dust with powdered xylitol, erythritol or lakanto.
Storage: Best served right away.