Red Currant Bakery

Brioche
0 Add  the flour, ground sugar, and yeast into the bowl of a stand mixer, and whisk to combine.
2 Sprinkle in the salt. Then add in the egg and warm milk.
3 Use a dough hook to knead everything together on medium low speed for 15 minutes until the dough has smooth edges and the bowl is clean.
4 Add half of the butter in and knead again until incorporated (about 5 minutes). Add in the second half of the butter and knead once more until smooth. The dough should pass the window pane test *see notes section for more info.
5 Line a quarter sized baking sheet with a sheet of plastic wrap. Shape the dough into a rough rectangle that is about an inch thick. Top the dough with another sheet of plastic wrap.
6 Immediately place the dough on the sheet pan into the fridge for at least an hour or up to overnight. I usually keep it in there for about 2 hours but make it work in your schedule!
7 Alternatively you can let it sit somewhere a little warm, covered with plastic, in the mixing bowl, for about 45 minutes until it has doubled in size.
Filling
9 Add the butter, both sugars, ground cinnamon, salt, and a splash of vanilla into a small mixing bowl and stir together until smooth.
10 It should be a spreadable consistency but not soupy. If it seems to soft, put it in the fridge and stir it every 5-10 minutes until it has thickened. If it's too firm it'll be difficult to spread on the dough so just microwave it in 5 second intervals, stirring in between until spreadable.
Crumb Topping
12 In a medium bowl add in the soft butter, both sugars, cinnamon, salt and vanilla. Use a fork to stir together until smooth.
13 Pour in the flour and use the fork to rub the flour into the butter mixture until fully combined.
Assemble
15 Preheat the oven to 350 F and place a rack in the center of the oven. Or just below if the heat comes from the top of the oven.
16 Line your loaf pan with a parchment paper sling that reaches from one long side to the other.
17 Once the dough has chilled (it won't grow much but should be a little puffy), or doubled in size at room temperature, unwrap it and tip it out onto a lightly floured work surface.
18 Roll it out to a 10" x 18" rectangle. Try to keep the dough as right angled as possible while rolling it out and use flour as needed to keep the dough from sticking.
19 Spread the cinnamon sugar butter over the entire surface of the dough.
21 Roll the dough up, starting with one short side. Roll it up tightly but make sure not to squeeze out the filling.
20 Once fully rolled, seal the edge of the dough to the roll by pinching the dough to the roll. Give the roll a few squeezes while also ever so slightly stretching it out.
22 Use a long sharp knife to cut the roll in half lengthwise. Open the two halves so that the cut sides are face up. Cross the two halves over one another creating an X.
23 Then, twist the two halves together keeping the cut sides face up. Pinch the ends of each half together to keep it from untwisting. Then twist the other half together and repeat pinching the ends.
24 Tuck the ends under the twist and lower it into the pan. You will have to scrunch the twist together a little to make it fit which will make the twist fatter. Gently press the twist down so that it reaches the sides of the pan.
25 Cover the pan with plastic and set aside for at 30-45 minutes to proof until puffy.
26 Once puffy crumble and gently press the crumb topping onto the top of the babka.
Bake
28 Place the loaf pan on a quarter or half sized baking sheet into the preheated oven. Close the door and bake for 30 minutes. 
29 After 30 minutes have passed, rotate the pan 180 degrees and bake for another 25-30 minutes. If you feel like it's starting to brown too much, tent a piece of foil over the top.
30 Make the glaze while the babka bakes.In a medium bowl, whisk the butter with powdered sugar and milk.
31 If it is too thin, add more powdered sugar, if too thick add more milk. It should be quite thick because the warmth of the babka will sort of melt it.
32 The twist should be a deep golden brown once done baking. Take the pan out of the oven and let it cool for 5 minutes. Drizzle the top with the glaze and then wait 5 minutes before lifting the babka out of the pan to finish cooling on a wire rack.
33 Allow the babka to cool for at least 30 minutes before cutting into it (if you can).