Lemon Brown Butter Shortbread

Ingredients

• 0.5 cup t brown sugar dark packed
• 1.5 cups flour all-purpose
• 2 teaspoons lemon zest grated
• 0.3 teaspoon sea salt 
• 12 servings sugar for sprinkling
• 12 tablespoons butter unsalted
• 1 teaspoon vanilla extract 

Equipment

• bowl
• frying pan
• baking sheet
• sauce pan
• oven
• knife
• wire rack
• cake form
• aluminum foil
• tart form

Directions

1. Lightly grease a 9 1/2-inch fluted tart pan with a removable bottom. Or, if you don't have a tart pan, line an 8-inch square cake pan with foil, leaving an overhang on two opposite sides so you can lift the shortbread out of the pan.
2. Melt the butter in a small saucepan over medium-low heat, then cook until the milk solids sink to the bottom, turn golden-brown, and smell toasty; be careful not to burn the butter.
3. Remove from heat.
4. Combine the brown butter with the brown sugar, vanilla, zest, and salt in a medium bowl.
5. Add the flour and mix until incorporated.
6. Spread the dough evenly in a prepared pan.
7. Let stand for 2 hours, or, preferably, overnight. (Do not refrigerate.)
8. Preheat the oven to 300°F.
9. Bake the shortbread for 45 minutes.
10. Remove the pan from the oven, but leave the oven on. Lightly sprinkle the surface of the shortbread with sugar.
11. Let cool for 10 minutes.
12. Very carefully remove the sides of the tart pan. Or, carefully remove the shortbread from the pan using the foil as a sling. Use a very sharp thin knife to cut it into 12 wedges or 9 squares. Carefully place the slices slightly apart on a baking sheet lined with parchment and return them to the oven for 15 minutes to toast lightly. Cool on a wire rack.