Preheat oven to a little under 400°F. The ... other words, 200°C. Melt chocolate and butter together in ... egg yolks and sugar. Whisk in flour and ... center will harden.) .
Stir together powdered sugar, flour and cornstarch. Cut ... thick round. Transfer to baking sheets (two cookies per ... tablespoons butter (one stick).
Ingredients: 4 (cornstarch .. sugar .. temperature ...)