I ventured into making brioche doughnuts just this morning. Make sure you start a day ahead as this dough needs about 24 hours to retard (rest) in the fridge overnight.
Eggs 300 g
Milk 212 g
Bread flour 751 g
Instant yeast 9 g
Salt 20 g
Butter 373 g
Sugar 112 g
|Mine are filled with apricot jam!|
Combine first five ingredients and 1/3 butter in a mixer with dough hook attachment. Mix on low for about 2 minutes until ingredients come together. Mix on high for 4 minutes. Then, while dough is mixing add all the sugar and butter (roughly chopped) to the dough. Mix on high until the butter and sugar is fully incorporated into the dough. Don't worry! This may take 10-15 minutes and your mixer may get fairly warm. Keep going until you have a very sticky but smooth dough and no butter pieces are visible. Stop the mixer to scrape down dough periodically to ensure an even mix. Lightly oil and butter a large bowl. Ball up dough and place into bowl. Wrap very well with plastic and place into fridge for about 24 hours but at least 12 hours. I left my dough in the fridge for about 36 hours and did not find my product to be damaged at all.
Take dough out of fridge the next day. It should have risen up a fair amount while in the fridge. Dust your hands with bread flour and dust the work surface you are using with bread flour so the dough does not stick. Weigh out 2 oz pieces. Using your hands form the pieces into balls and flatten the balls with your palms so they look like rounded discs. Allow doughnuts to rest at room temperature for about an hour to an hour and a half. The doughnuts should look puffy and the dough should definitely have risen noticeably.
When you notice the dough is almost ready start heating up canola oil in a pan with high sides. You will need to fill the pan so that it is about 2-3 inches deep with oil. Also prepare a plate with sugar mixed with cinnamon to taste. You will need enough cinnamon sugar to coat all the doughnuts. Heat up the oil to 350 degrees F. This is the optimal frying temperature for doughnuts so keep an eye on it as you start frying. Prepare a metal rack for the hot doughnuts or if you don't have one line plates with paper towels to absorb extra oil.
Add the doughnuts to the pan but do not crowd them. Using wooden sticks (or two forks) turn them when they are golden brown on one side. Place them on the paper towels and allow the towels to soak up the extra oil. When the doughnuts have cooled slightly but are still warm roll them in the cinnamon sugar. When they are completely cool fill a piping bag fitted with a number 2 tip with your favorite jam and pipe it into the doughnuts from the side. Enjoy!