- 2 sticks (1 cup) unsalted butter
- 1/2 cup packed light brown sugar
- zest of two limes (at least 2 Tbsp)
- 1 vanilla bean, seeded (or 1/2 tsp ground vanilla bean)
- 1 egg
- 1/4 cup fresh lime juice
- 2 1/4 cups all-purpose flour
- 2 Tbsp cornstarch
- 1/4 tsp salt
- In a shallow pan, melt the butter over medium heat. Stir and swirl frequently as the butter pops and crackles. Once the crackling has subsided, stir continually and watch for browning. As soon as the solids have browned, and the butter smells nutty, remove from heat and pour into a separate container.
- Refrigerate (or freeze) until solid. Before continuing, bring the butter back to room temperature (it should still be solid, but not rock hard).
- Combine the butter (make sure to scrape all of the brown flecks in, too!), brown sugar, lime zest, and vanilla seeds in the bowl of a stand mixer. Mix together until light and fluffy.
- Add the egg, mixing until fully incorporated.
- Add the lime juice, again mixing until incorporated.
- In a separate bowl, combine the flour, cornstarch, and salt. Whisk together, then add to the wet ingredients and mix until just combined. Do not overmix.
- Divide the dough into two parts, and roll in plastic wrap to form logs. Freeze for 30 minutes.
- When ready to bake, cut the dough into 3/8" thick slices, and bake on a parchment-lined baking sheet at 350 F for 10-11 minutes. If the edges of your cookies are browning AT ALL, they are done.
- Let cool on the baking sheet for a minute before transferring to a cooling rack.