½ cup turbinado sugar or regular sugar, divided
1 ½ cups almond meal
1 cup all-purpose flour
¾ cup unsalted butter, at room temperature
2 teaspoons lemon zest
1 Tbsp. fresh lemon juice (2 lemons)
2 teaspoons poppy seeds
1 teaspoon chopped fresh thyme
¼ teaspoon fine salt
Process ¼ cup of the sugar in a food processor until sugar begins to look like fine sand, about 1 minute. Add almond meal, flour, butter, lemon zest, lemon juice, poppy seeds, thyme, and salt to processor. Process until dough just comes together, about 30 seconds. Separate dough into 2 equal portions; roll each portion into a 9 x 1 ½- inch log and wrap each log tightly in plastic wrap. Freeze at least 2 hours or overnight.
Preheat oven to 300 F. Line rimmed baking sheets with parchment paper. Place remaining ¼ cup sugar on a plate; roll dough log in sugar to coat evenly. Slice 1 log into 32 (1/4-inch-thick) slices. Place cookies 1 inch apart on lined baking sheets. Bake in preheated oven until golden, about 20 minutes. Remove from oven and let cool 5 minutes on baking sheets. Transfer to wire racks to cool completely at room temperature, about 30 minutes. Repeat with remaining dough.