• In a big bowl, mix together flour, sugar, and salt. Make a well in the middle.
• Pour in milk, beaten egg and melted butter into the well. Add the instant dry yeast to the liquid pool and stir using a wooden spoon within the well just to hydrate the yeast a bit.
• From inside the well, stir outward to mix the dry ingredients to the wet ingredients until a sticky dough forms. Tip the dough on a floured surface and knead until it becomes smooth and elastic, about 8-12 minutes.
• Form the dough into a ball and lightly coat with oil. Place it in a bowl and cover with a kitchen towel or plastic wrap and place it in a warm area and let it rise until it doubles in size. Depending how warm it is, it could take 30 minutes to an hour. Meanwhile, cut 16 pieces of 3x3-inch parchment or wax paper.
• Punch down the dough and transfer to a lightly floured surface. Divide the dough into 16 equal pieces. Cover the pieces with a damp kitchen towel or plastic wrap so they will not dry out.
• Form each piece into a smooth ball then place on a parchment paper. Lightly press it to flatten just a bit. Repeat with the rest of the dough. Cover with a kitchen towel and let them rise again to almost double.
• Start to heat the oil in a wide pan over medium heat (160°C-170°C). Oil must be at least 1 ½ -2 inch deep. Fry in 3-4 batches, so it will not be overcrowded. Slide a piece of dough with parchment paper into the oil using a flat spatula or bench scraper. Fry until the bottom part is light golden brown then flip them over, and cook until the color of both sides evens out, around 3-5 minutes per batch. Just remove the parchment paper once it detaches from the dough or after turning it over.
• Remove from oil using a strainer spoon and transfer to a baking sheet lined with paper towels. Let them cool down enough to handle.
• In a wide bowl, run powdered sugar and cornstarch through a sieve. Set aside.

TO MAKE CREAM FILLING

• Warm milk in a saucepan over medium heat until it starts to simmer but do not let it boil. Once it starts to simmer, turn the heat off.
• In a bowl, combine sugar and cornstarch and mix. Then add the egg yolks and beat with a whisk until it becomes smooth and lighter in color.
• Add ¼ cup of the hot milk and whisk, then, another and whisk again until. Then add the egg mixture to the rest of the hot milk in the saucepan and turn on the heat again to medium. Cook while whisking regularly until it becomes a thick smooth paste. Turn heat off and add the butter and whisk until completely it turns shiny. Add the vanilla extract and mix.
• Let it cool down and then transfer to a piping bag with a piping tip.
• Roll the fried doughnut in powdered sugar mixture. Then insert a chopstick from the side through the middle going all the way to the three-quarters of the doughnut. Wiggle it inside on the way out to create a cavity for the filling to fill in.
• Pipe enough cream filling to fill the cavity created.
• Transfer to a serving tray and enjoy.