01 - Cream butter and powdered sugar in large bowl until smooth and fluffy. Beat in vanilla extract until incorporated.
02 - Sift flour and salt into 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 minimum 30 minutes.
04 - Heat oven to 350°F and line baking sheets with parchment paper.
05 - Cut chilled dough logs into 1/2-inch thick rounds. Place on prepared baking sheets, spacing 1 inch apart.
06 - Bake for 12-14 minutes until edges are just turning golden brown. Cool completely on baking sheets.
07 - Whisk egg yolks, granulated sugar, heavy cream, and vanilla in small saucepan. Cook over medium-low heat, stirring constantly, until mixture thickens slightly, about 4-5 minutes. Remove from heat and cool completely.
08 - Spoon small amount of cooled custard onto center of each cookie. Gently spread to create even layer.
09 - Sprinkle thin layer of granulated sugar over custard on each cookie. Use kitchen torch to melt and caramelize sugar until golden brown and crispy. Let set 5 minutes before serving.