Heat a large sauté pan over medium heat and add butter.

Cook butter until it begins to brown, about 5 minutes. Remove from heat and add 1 tsp vanilla extract and 1/2 tsp ground cinnamon.

Let brown butter cool. In the meantime, sift together AP flour, black cocoa powder, 1 tsp kosher salt, baking powder, and baking soda into a large bowl.

Once brown butter is warm, not hot, add brown sugar and white sugar and mix into a slurry. Then, add your egg and egg yolk and whisk to combine.

Pour your dry ingredients into the brown butter mixture and fold until combined with a spatula.

Line a sheet pan with parchment paper. Scoop 8 equal balls onto the baking sheet (two scoops with a melon baller for each cookie).

Press a tablespoon into the center of each cookie ball to create a well. Place pan in the freezer for 10-15 minutes until firm.

Preheat oven to 350°F. Bake cookies for 14-16 minutes until firm and re-dimple the centers with the tablespoon when they come out of the oven. Let cool.

Chop dark chocolate and place in a large heat-proof bowl. Heat heavy cream with 1/2 tsp kosher salt, 1/2 tsp vanilla extract, and 1/2 tsp coffee extract in a sauce pan until scalding.

Pour over the chopped chocolate and let stand for 30 seconds. Then, stir into a silky ganache.

Spoon ganache into each cookie crevice, being careful not to overflow. Top with a touch of sea salt, sprinkles, or fruit zest and let stand until set (30 - 60 minutes).