In a small saucepan, brown ½ cup of your butter by melting it, it will break down into separate liquid fat and milk solids. The milk solids are what will become toasted brown, make sure to stir often to move around the milk solids so they don't burn.

Beat browned butter, ½ cup softened butter, maple syrup, sugar, and vanilla extract until light and fluffy. Add in flour and salt, mix until just combined. There will be large pieces of dough.

Create maple sugar by putting about a teaspoon of maple syrup on a plate or flat surface and stir in coarse sugar until not clumpy, but slightly wet. Set aside for the next step.

Roll the dough into a log with flat ends on either side. Completely cover the log with the maple sugar but leave the ends bare. Immediately roll the dough into a plastic/cling wrap and refrigerate for 30-60 minutes.

Preheat oven to 350 F. Using a sharp knife cut the log into 12 even pieces by cutting the log in half, then those 2 halves into halves- making quarters, then cut 3 even pieces out of the 4 quarters.

Place the slices on a cookie sheet and bake for about 15-18 minutes or until golden. Brush with maple syrup and top with flakey sea salt. Let cool for at least 10-15 minutes.