Prep: 1. Melt and cool butter. 2. Zest lemons. Make: 1. In a medium bowl, whisk together butter, agave, zest, vanilla, and egg. 2. In a large bowl, whisk together flour, cornmeal, baking powder, and salt. Add butter mixture to flour mixture and stir until well combined. 3. Cover and chill dough until cold and firm, at least 2 hours 4. Preheat oven to 350. Line a large baking sheet with parchment paper. 5. Place pistachios in a medium bowl. 6. Form cookies into 2 tablespoon balls and roll in pistachios to coat. 7. Bake until puffed and golden brown on the bottom, 13 to 15 minutes.