First, make the malasada dough. In the bowl of a stand mixer fitted with a dough hook, combine the flour, sugar, yeast, and salt. Knead on low to combine, about 30 seconds. Press a tall glass or measuring cup in the center of the ingredients to make a "well."

Whisk the wet ingredients. In a large liquid measuring cup, whisk together the milk, egg, egg yolk, and butter.

Knead the dough. Pour the wet ingredients into the well in the dry ingredients and knead on medium-low for 10 minutes, or until smooth and elastic, using a rubber spatula to scrape down the bottom and sides of the bowl as necessary. The dough will be sticky and thick. It will look more like batter at this point, but that's totally okay, I promise!

Proof the dough overnight. Cover with plastic wrap and refrigerate overnight.

While the dough is proofing, make the passion fruit pastry cream. In a medium, heavy-bottomed saucepan, whisk together ¼ cup (1.75 ounces or 50 grams) of the granulated sugar and the milk. Cook over medium-low heat, whisking continuously, 2 to 3 minutes or until the milk begins to steam. Reduce the heat to low.

Whisk together the egg, cornstarch, and remaining sugar, then temper it with the hot milk mixture. In a medium, heatproof bowl, whisk together the egg, cornstarch, and remaining sugar.Slowly ladle ¼ cup of the hot milk mixture into this egg mixture, whisking the egg mixture continuously. Pour the egg mixture into the saucepan with the remaining hot milk mixture and bring to a boil over medium heat, whisking continuously. Immediately remove from heat.

Add the butter, passion fruit, and vanilla. Immediately add the butter, passion fruit, and vanilla and whisk until smooth.

Chill the pastry cream overnight. Place a fine-mesh sieve over an airtight container with a lid and pour the pastry cream through the sieve to remove any lumps. Set the bowl on a wire rack. Press a sheet of plastic wrap directly against the surface of the pastry cream and cool completely. Cover with the lid and refrigerate overnight.

Form the dough into malasadas. Line a half sheet pan with parchment paper and generously flour the paper. Remove the dough from the refrigerator. Uncover it and discard the plastic wrap. Tip the dough onto a generously floured counter. Use a rolling pin to roll the dough into a rectangle about ½-inch thick. Use a 3-inch round cookie cutter to cut out 6 circles. You may need to gather and reroll the dough.

Proof the malasadas. Place the circles at least 3 inches apart on the prepared sheet pan. Loosely cover with plastic wrap and let rise for 1 hour.

Prep your frying and assembly station. Fill a heavy-bottomed pot with tall sides (like a Dutch oven) or deep-fryer halfway up with vegetable oil. Affix the deep-fry thermometer in the pot or deep-fryer and heat the oil to 365°F.Line a wire rack with two sheets of paper towels.Place the ¾ cup of granulated sugar for assembly in a shallow bowl.Scrape the chilled passion fruit pastry cream into a piping bag fitted with a Bismark pastry tip.

Fry the malasadas. Carefully remove the donuts by wedging a floured bench scraper underneath each one. Working in batches of 2 donuts at a time, fry for 2 minutes on each side, or until the donuts are puffy and golden brown. Once done, use a slotted spoon to move the donuts to the prepared wire rack. Repeat until all the donuts are fried, making sure that the oil temperature is at 365°F every time you start a new batch.

Assemble the malasadas. Toss each donut in the shallow bowl of sugar while still warm from the fryer. To fill each donut, wait 15 minutes to allow the donuts to cool slightly and then use a skewer or a Bismark pastry tip to poke a hole in the side of each donut.Pipe the pastry cream into the holes until each donut is plump and swollen, around 2 Tablespoons each. The donut should be stretched thin to the point of bursting.

Serve and store. Serve warm or at room temperature. The malasadas are best the day they’re made, but you can store any leftovers under a cake dome or a large bowl turned upside down for up to 1 day. After 1 day, transfer to an airtight container and refrigerate for up to 2 more days.