Ingredients

• 1 cup (2 sticks) unsalted butter, room temperature
• 1/2 cup (packed) light brown sugar
• 2 1/4 cups all-purpose flour
• 2 tbsp cornstarch
• 1/2 tsp salt
• 2 tbsp plus 2 tsp black sesame seeds

Instructions

1. Preheat oven to 325° with racks in center and upper third. Line 2 baking sheets with parchment paper.
2. Beat butter and sugar until light and fluffy.
3. Whisk together flour, cornstarch, salt, and sesame seeds. Add flour mixture to butter mixture, 1 cup at a time, beating after each addition until incorporated. Transfer mixture to a surface and knead into a smooth dough. Wrap in plastic and refrigerate for 20 minutes.
4. Transfer chilled dough to a lightly floured surface; roll into a 1/2"-thick rectangle. Cut into 2" squares, then cut each square into triangles. Transfer to prepared baking sheets.
5. Bake until edges are light golden brown, 20-22 minutes. Let cool.