Cream butter, sugar, and honey together until light and fluffy.
Add egg and mix until fully combined, being sure to scrape the sides and bottom of the bowl.
Combine both flours, baking powder, salt, and cinnamon in a bowl.
Add flour mixture to butter mixture in two parts and mix until a smooth dough is formed.
Split dough in two parts, and roll out each to 1/16th of an inch thick (about the thickness of a craft single) between two sheets of parchment paper.
Refrigerate dough for at least 30 minutes.
Preheat oven to 300.
Remove dough from fridge and brush with milk.
Bake for 10 minutes.
Remove from oven and trim sides to form clean rectangle. Cut rectangle into twelve 2-2 ½ inch squares. Leave scraps on the pan to protect the edges of the crackers.
Return to oven and bake for another 8-10 minutes, until trim begins to brown.
Turn oven off and leave crackers to cool in oven with the door ajar.
Store in an airtight container for up to 4 days.