01 - In a large bowl, beat unsalted butter and powdered sugar until smooth and fluffy. Incorporate vanilla extract until fully blended.
02 - Sift flour and salt into the butter mixture. Mix until just combined and dough forms without overworking.
03 - Divide dough in half and shape into 2-inch diameter logs. Wrap tightly in plastic wrap and refrigerate for at least 30 minutes.
04 - Preheat oven to 350°F. Line baking sheets with parchment paper.
05 - Slice chilled dough logs into 1/2-inch thick rounds. Place on prepared baking sheets, spacing 1 inch apart.
06 - Bake for 12 to 14 minutes until edges are lightly golden. Transfer to wire rack and cool completely.
07 - Whisk egg yolks, granulated sugar, heavy cream, and vanilla paste in small saucepan. Cook over medium-low heat, stirring constantly, until thickened, 4 to 5 minutes. Remove from heat and cool completely.
08 - Spread small amount of cooled custard onto center of each cookie using offset spatula.
09 - Sprinkle thin layer of granulated sugar over custard. Torch sugar until golden and crispy. Let set 5 minutes before serving.