Boston Cream Donut

In a large stand mixer bowl, combine 420g all-purpose flour, 7g instant yeast, 50g granulated sugar, and 1 tsp fine salt. Add 120ml warm (43°C/110°F) whole milk, 2 room-temperature whole eggs, and 57g melted, slightly cooled unsalted butter. Mix with a dough hook attachment on low speed for 5 minutes until a smooth, elastic dough forms that pulls cleanly away from the bowl sides. Cover the bowl tightly with plastic wrap and let rest in a warm, draft-free spot for 60 minutes until doubled in volume.

While the dough rises, heat 240ml whole milk in a small heavy-bottomed saucepan over medium-low heat until it just begins to steam (approximately 82°C/180°F, do not boil). In a separate medium bowl, whisk 2 egg yolks, 50g granulated sugar, 2 tbsp cornstarch, and a pinch of fine salt until completely smooth. Slowly pour 1/3 of the warm milk into the yolk mixture while whisking constantly to temper the eggs and prevent curdling, then pour the combined mixture back into the saucepan. Cook over medium-low heat, whisking nonstop for 2 to 3 minutes until the cream is thick enough to leave a clear line when a finger is drawn across the back of a coated spoon. Remove from heat, stir in 28g unsalted butter and 1 tsp vanilla extract, then transfer to a shallow bowl, press plastic wrap directly to the cream’s surface, and chill in the refrigerator for 45 minutes.

Once the dough has fully doubled in size, punch it down firmly to release all trapped air, then roll it out on a lightly floured work surface to an even 1.25cm (½-inch) thickness. Use an 8cm (3-inch) round biscuit or donut cutter to cut 8 uniform rounds, re-rolling dough scraps only once to avoid tough donuts. Place the cut donuts 5cm (2 inches) apart on a parchment-lined baking sheet, cover loosely with a clean linen kitchen towel, and let proof in a warm spot for 30 minutes until puffy and slightly jiggly when the tray is gently tapped.

Heat 1L of neutral vegetable oil (canola or peanut) in a deep, heavy-bottomed pot to 175°C/350°F over medium heat, monitoring temperature with a clip-on candy thermometer. Carefully lower 2 to 3 donuts at a time into the hot oil, taking care not to splash or overcrowd the pot, which drops oil temperature. Fry for 90 seconds per side until deep, even golden brown, then use a slotted metal spoon to transfer donuts to a wire rack lined with paper towels to drain for 10 minutes. Bring the oil back to exactly 175°C/350°F between each batch to ensure even cooking.

Once fried donuts are cool enough to handle (about 10 minutes after draining), use a small sharp paring knife to cut a 2cm (¾-inch) wide slit in the side of each donut, wiggling the knife gently inside to create a hollow pocket for filling. Transfer the chilled, set pastry cream to a piping bag fitted with a 1cm (½-inch) round piping tip. Insert the tip into the slit in each donut, and pipe approximately 2 tbsp (30g) of cream into the center, stopping when the donut feels noticeably heavy and slightly puffed from the filling.

Make the chocolate glaze by heating 60ml heavy cream in a small saucepan over low heat until it just reaches a gentle simmer (do not boil). Pour the hot cream over 113g of finely chopped semi-sweet chocolate in a heatproof glass bowl, let the mixture rest undisturbed for 2 minutes to melt the chocolate, then stir in 1 tbsp light corn syrup and 1 tsp vanilla extract until the glaze is completely smooth and glossy. Dip the top half of each filled donut into the warm glaze, letting excess glaze drip back into the bowl for 10 seconds, then place donuts back on the wire rack for 15 minutes to let the glaze set before serving.