Use a mixer only. Paper muffin cups - medium size. Muffin tray.
Dissolve the yeast in the warm milk until the yeast forms small bubbles along the edges. Pour it into the mixing bowl, add the slightly whipped eggs and the lemon zest. Stir with a spatula. Add the sifted flour, sugar and salt.
Turn the mixer on slow for 3-4 min. to combine the components. Without stopping it, gradually add the pieces of butter and beat on medium for 5-6 min. until all of the butter is absorbed by the dough and it starts wrapping around the beaters. It needs to be a thick, smooth, sticky mass. Transfer it to a deep bowl, cover with foil and place in the fridge overnight.
The next morning, take it out, put it onto a floured counter and divide into 2 parts. Knead each part again carefully. While working with 1 part, return the other to the fridge. The dough is very easy to work with when it's cold; if it starts to stick, return it to the fridge briefly.
Form the brioches as follows: Take a dough ball the size of a large apricot, rub it between your palms, thinning it out at one end but leave a small ball at the end of the dough. Put it on the counter, make a hole with your finger in the large ball and stick the neck with the smaller ball through it. Then form into a round shape with your hands.
Place in the paper cups in the muffin tray. Smear with egg yolk and leave to rise again for 30 min. Before baking, smear with egg yolk again, sprinkle generously with cinnamon sugar or coarse sugar and bake at 347°F (175 °C) for 25-30 min. to a golden brown.
Source: Cause It`s Always Delicious.
Notes: Traditionally, brioches don't have a filling but you can add some if you like. For a stronger aroma I added 2 drops of Fiori Di Sicilia orange and vanilla extract.
The ingredients listed yielded 12 brioches in the muffin tray. I used the remaining dough to make 1 large brioche.
After beating with the mixer, the dough is really sticky at the beginning and impossible to work with but after 1 night in the fridge it's light, fluffy and easy to work with. You can use vanilla extract or other flavors if you like.