01 - Cream butter and powdered sugar in a large bowl until smooth and fluffy. Beat in vanilla extract.
02 - Sift flour and salt into the butter mixture. Mix until just combined and dough forms.
03 - Divide dough in half and shape into 2-inch diameter logs. Wrap in plastic and refrigerate for at least 30 minutes.
04 - Preheat oven to 350°F and line baking sheets with parchment paper.
05 - Slice chilled dough into 1/2-inch thick rounds. Place on prepared baking sheets and bake for 12–14 minutes until edges are golden. Cool completely.
06 - Whisk egg yolks, granulated sugar, heavy cream, and vanilla in a small saucepan. Cook over medium-low heat, stirring constantly, until slightly thickened, about 4–5 minutes. Remove from heat and cool completely.
07 - Spoon cooled custard onto center of each cookie. Sprinkle thin layer of granulated sugar over custard. Use kitchen torch to caramelize sugar until golden and crisp. Let set 5 minutes before serving.