01 - In a small bowl, combine the warm milk, instant yeast, and a spoonful of sugar. Stir gently and let the mixture rest for 5 minutes until it becomes foamy and activated.
02 - In a stand mixer fitted with a dough hook, combine the flour, remaining sugar, and salt. Add the eggs and proofed yeast mixture. Knead on medium speed for 5 minutes. Gradually add the softened butter in small pieces, continuing to knead until the dough is shiny, smooth, and elastic, about 10 minutes. Cover the bowl and let the dough rise for 1 hour or until doubled in size.
03 - In a saucepan, heat the milk over medium heat until steaming but not boiling. In a separate bowl, whisk together the egg yolks, sugar, cornstarch, and salt until the mixture turns pale. Slowly pour the hot milk into the yolk mixture while whisking constantly to temper. Return the mixture to the saucepan and cook over medium heat, whisking continuously, until thickened, 3 to 5 minutes. Remove from heat, stir in the vanilla extract, and press plastic wrap directly onto the surface to prevent a skin from forming. Let cool.
04 - Preheat the oven to 350°F. Punch down the risen dough and transfer to a lightly floured surface. Roll into a 12-inch circle and place on a parchment-lined baking sheet or pizza pan. Use your fingers to create a slight raised rim around the edges.
05 - Spread the cooled custard evenly over the dough, leaving a 1/2-inch border around the edge. Sprinkle with 2 tbsp granulated sugar to promote caramelization. Arrange fresh fruit on top if desired. Bake for 22 to 25 minutes until the crust is golden and the custard is lightly set. Cool slightly before slicing into 8 wedges. Dust with powdered sugar if desired before serving.