Custard Bun Recipe

Prepare thickener

Whisk the cornstarch and 1 tablespoon sugar together in a small bowl. Add 1–2 tablespoons of the cold milk from the measured 1 cup and whisk to make a smooth slurry (no lumps).

Temper yolks

In a separate bowl, whisk the 2 egg yolks until smooth. Set aside.

Heat milk

Place the remaining milk in a small saucepan with a pinch of salt and bring to a gentle simmer over medium heat, stirring occasionally so it doesn't scorch. Remove from heat just as small bubbles form at the edge.

Combine and thicken

Temper the yolks by slowly pouring about 1/3 of the hot milk into the yolks while whisking constantly. Then pour the tempered yolk mixture back into the saucepan with the rest of the hot milk. Return to medium-low heat and whisk in the cornstarch slurry continuously until the mixture thickens to a pudding-like consistency (2–4 minutes). Do not boil vigorously.

Finish custard

Remove from heat, stir in 1 tablespoon butter and 1 teaspoon vanilla extract until smooth. Taste and add up to 1 more teaspoon sugar if you prefer it sweeter. Transfer custard to a bowl, press plastic wrap directly onto the surface to prevent a skin, and chill in the refrigerator until cool (about 1 hour).

Activate yeast

Warm the 1 cup of milk to about 38–43°C (100–110°F). In a small bowl combine the warm milk, 1 tablespoon sugar, and 2 teaspoons instant dry yeast. Let sit 5–7 minutes until foamy. (If using active dry yeast, proof 8–10 minutes.)

Mix dough

In a large bowl or the bowl of a stand mixer, combine 3 cups all-purpose flour and 1 teaspoon salt. Add the foamy yeast-milk mixture, 1 whole egg, 3 tablespoons softened butter, and 1 teaspoon oil. Mix with a dough hook or wooden spoon until a shaggy dough forms.

Knead

Knead the dough on medium speed or on a lightly floured surface for about 8–10 minutes until the dough is smooth, elastic, and slightly tacky. If too sticky, add up to 2 tablespoons flour, 1 tablespoon at a time.

First rise

Shape the dough into a ball, place in a lightly oiled bowl, cover with plastic wrap or a damp towel, and let rise in a warm draft-free place until doubled in size, about 60–75 minutes.

Divide and rest

Punch down the risen dough and turn it out onto a lightly floured surface. Divide the dough into 12 equal pieces (about 50–55 g each). Shape each piece into a smooth ball and let them rest 10 minutes, covered, so the gluten relaxes.

Fill buns

Flatten each rested dough ball into a 3.5–4 inch (9–10 cm) circle, slightly thicker in the center. Place about 1–2 tablespoons of chilled custard in the center of each circle (enough to form a small mound but not overflow). Gather the dough edges up around the custard and pinch to seal tightly. Roll the sealed seam gently on the counter to form a smooth bun. Place seam-side down on a baking tray lined with parchment paper, leaving 1.5–2 inches between buns.

Final proof

Cover the shaped buns loosely with plastic wrap or a damp kitchen towel and let them proof in a warm place until puffy and nearly doubled, about 35–45 minutes.

Egg wash & seeds

Preheat the oven to 180°C (350°F). Whisk 1 whole egg with 1 teaspoon water for an egg wash. Gently brush the tops of the proofed buns with the egg wash and sprinkle sesame seeds on top if desired.

Bake

Bake in the preheated oven for 14–17 minutes, rotating the pan halfway through, until the buns are golden brown on top and sound hollow when tapped lightly. Avoid overbaking to keep the interior soft.

Cool

Transfer buns to a wire rack and cool for at least 10 minutes before serving so the custard sets slightly. Serve warm or at room temperature. Store leftover buns in an airtight container in the refrigerator for up to 3 days; gently rewarm in a microwave for 10–12 seconds before serving.