Proof the yeast by mixing it with the milk and a pinch or two of sugar and letting it rest for 10 minutes. It should form a frothy foam on the milk. If this does not happen, you may need fresher yeast.

Mix together the flour, sugar, and salt together, then slowly mix the flour and milk mixture together until a dough forms. Add the eggs one at a time until completely incorporated. Add in the butter a tablespoon at a time in the same manner.

Lightly grease a bowl and place the dough in. Cover with plastic wrap. Allow to rise for 1 hour. Punch down the dough and roll out until about ½ inch thick. Use a doughnut cutter or mouth of a cup to cut out doughnuts that are about 3 ½ inches in diameter. Re-roll any excess dough and cut. Place the doughnuts on a greased sheet of parchment paper. Cover with plastic wrap and allow it to rise for another hour.

Heat at least 3 inches of oil to 375 degrees F. Fry each doughnut until a deep golden brown - about 2 - 3 minutes on each side. You should be able to fit roughly three doughnuts in a pan or deep fryer depending on the size. Just make sure the doughnuts do not touch while frying. Allow the doughnuts to drain and cool completely on a wire rack covered in paper towels.

Add the ingredients into a small saucepan. Bring to a boil, then simmer for about 5 minutes, or until the mixture is reduced to ½ a cup. Set aside to cool.

In a medium saucepan, heat the milk and vanilla until it begins to steam and simmers around the edges. Do not let it boil.

Mix together the sugar, cornstarch, salt and egg yolks together and whisk until light in color. Slowly temper the eggs by adding ⅓ of the milk into the eggs slowly and whisking constantly as you drizzle in the milk. Repeat with another ⅓ of the milk. Slowly pour the egg mixture back into the saucepan with the remaining milk.

Whisk the mixture constantly until the mixture begins to boil. Turn down the heat and whisk quickly for another two minutes. The mixture should thicken as you whisk. Remove the mixture from the heat and slowly whisk in the butter, one tablespoon at a time. Pour the mixture into a pan and allow it to cool for about 5 minutes. Cover the top with plastic wrap so that the plastic touches the cream. Chill in the refrigerator.

Take out the chilled pastry cream and whisk in half the blood orange syrup until completely combined. Swirl in another couple of tablespoons, but do not mix in entirely. Fit a pastry bag with a small round tip and brush the insides with more of the blood orange syrup before adding in the pastry cream.

Mix the sugar and blood orange zest together. Rub the mixture between your fingers to help release the oils from the zest into the sugar.

Use a skewer or small rod to poke a hole through the side of the doughnuts. (I used the end of a wooden spoon). Fill the doughnut with some of the pastry cream so that the doughnut feels heavier, but not bursting. Roll the doughnuts in the blood orange sugar. If the sugar is having a tough time sticking to the doughnuts, lightly brush the doughnuts with a bit of melted butter and re-roll.