Method

Put the yeast, milk, and water in the bowl of a stand mixer and stir gently to combine. Let the mixture sit until small bubbles appear, this should take roughly 5 minutes.

Add the flour and salt to the yeast mixture, then use the dough hook on your mixture to stir the flour into the yeast mixture on a low speed. Be sure to stop the mixer a few times to scrape the sides of the bowl and pull up any leftover yeast from the bottom of the bowl. Don’t stress if the dough is bitty and a little dry.

Add the eggs and sour cream or yoghurt to the floury mix. Mix gently to combine, then add the sugar. Turn the mixer up to medium-low and mix until the dough forms a smooth ball. Take care to stop and check that all the dry bits at the bottom are being incorporated – you may need to turn the mixer off and get your hands in there.

Turn the mixer back down to a low speed and mix the butter into the dough, a tablespoon at a time, beating until each piece is almost completely incorporated before adding the next piece. Be patient with this step to ensure that the dough is evenly mixed and kneaded. Stop periodically to pull the dough from the hook and scrape the sides of the bowl to ensure even mixing. Don’t panic if it looks like the bowl is getting very slick with butter, simply stop the mixer and scrape down the sides. The dough will be very soft. Once all of the butter has been incorporated, continue to knead the dough for at least 10 minutes or until it pulls away from the sides of the bowl and is completely smooth.

Transfer the dough to a clean bowl and let it rise at room temperature (nowhere too hot, though, as the butter will melt!) until it has doubled in size, this can take anywhere from 30 minutes to an hour so be patient. Knead the dough in the bowl a few times to release the air, then wrap with clingfilm and pop the bowl in the fridge. Let the dough overnight in the fridge. If you wanted to, you can leave in the fridge for up to 24 hours.

When you are ready to bake, remove the dough from the fridge and weigh it. Divide the weight by 4. Roll each piece into a ball and arrange the dough balls into a greased loaf pan. Cover the loaf pan lightly with a piece of buttered clingfilm and cover with a tea towel. Leave to double in size at room temperature. Keep an eye on the dough, as if it gets too warm the butter will leach out. This proving process can take up to two hours, so be patient. Preheat oven to 210 °C. When the dough has doubled, brush it with an egg wash.

Bake the loaf for 25 to 35 minutes, or until deep golden brown. You can check if it’s done by tapping the bottom of the loaf pan, use oven mitts or tea towels so hold the pan, though, as it will be very hot. Let the brioche cool in the pan for 5 minutes, then remove to a rack to cool completely.