Warm 1/2 cup of the Milk until lukewarm (about 110°F / 43°C) and stir in 1 tablespoon of the White Sugar and the Instant Dry Yeast. Let sit 5–10 minutes until foamy to proof the yeast.
In a large bowl whisk together 3 cups of Cake Flour, 1 teaspoon Salt and 2 tablespoons White Sugar. Create a well and add the proofed yeast, 2 Eggs (lightly beaten), the remaining warm Milk and 4 tablespoons of softened Butter.
Mix until a soft dough forms, then knead on a floured surface about 8–10 minutes until smooth and elastic. Place the dough in a lightly oiled bowl, cover, and let rise in a warm place until doubled in size, about 1–1.5 hours.
While the dough rises, make the crème filling: whisk together 2 Eggs, 1/2 cup White Sugar and 3 tablespoons Corn Flour until smooth. Gradually whisk in 1 1/4 cups of Milk and bring to a gentle simmer in a saucepan over medium heat, stirring constantly until thickened. Remove from heat and stir in 1 teaspoon Vanilla Essence and 1 tablespoon Butter. Chill the custard until thick and cold.
Punch down the risen dough and roll out to about 1/2 inch thickness. Cut rounds with a 2.5–3 inch cutter, place on a baking sheet, cover lightly and let rest 20–30 minutes to puff.
Heat about 2 inches of Water of oil? — (Note: use neutral frying oil) in a heavy pot to 350°F (175°C). Fry the donuts in batches, a few at a time, 1–2 minutes per side until golden. Drain on paper towels and let cool slightly.
Fill a piping bag fitted with a small tip with the chilled custard and inject each donut through the side or top until filled. Optionally dust the tops with a thin even layer of White Sugar.
Caramelize the sugar: use a kitchen torch to melt and brown the sugar crust until glassy and golden. If you don't have a torch, place the sugared donuts under a very hot broiler for a minute or two—watch carefully so they don't burn.
Serve the crème brûlée donuts warm or at room temperature so the crisp caramel top contrasts with the creamy custard inside.
