Red Currant Bakery

Brioche
0 In the bowl of a stand mixer whisk together the flour, sugar, and yeast.
2 Sprinkle in the salt. Then add in the warm milk, two eggs, butter, and vanilla extract.
3 Use a dough hook to knead everything together on medium low speed for 20-25 minutes until the dough has smooth edges and the bowl is clean.
4 The dough should pass the window pane test. This means that if you tear off a piece of dough, it can stretch until light passes through without tearing first.
5 Shape the dough into a ball and then place it back in the mixing bowl. Cover the bowl with a lid or plastic wrap and leave to proof for 45 minutes - 1 hour.
Fillings
7 In a medium mixing bowl add in 150 grams of butter, 125 grams sugar, 1.5 tablespoons ground cinnamon, 1/4 teaspoon fine sea salt, and 1 teaspoon vanilla extract. Use a fork to mix it together until smooth.
8 In a separate bowl, stir together the remaining 75 grams of sugar and 1.5 tablespoons of cinnamon.
Shape
10 Preheat the oven to 350 F and place a rack in the center of the oven.
11 I used these cake rings on baking sheets to bake the layers so I lined the baking sheets with parchment paper. But if you're using springform pans with tall edges, just line the bottom of the pans with parchment.
12 Divide the dough into 2/3 and 1/3 so if it weighs 999 grams, you'll have one portion that is 666 grams and 333 grams.
13 Start with the smaller portion of dough and roll it out on a lightly floured surface to at least 10" x 8". Try to keep the dough as rectangular as possible while rolling it out and use flour as needed to keep the dough from sticking.
14 Spread 1/3 of the cinnamon sugar butter filling over the entire surface of the dough.
15 Sprinkle the cinnamon sugar over the butter filling.
16 Roll the dough up, starting with one long side. Be careful to keep the roll tight but don't squeeze out the butter.
17 Once fully rolled, place it seam side down and give the roll a few squeezes while also ever so slightly stretching it out.
18 Use a long sharp knife to cut the roll in half lengthwise. Twist the two halves together with the filling face up. Start by crossing the two over each other to make an X shape, then twist towards both ends. Pinch the ends together so that you have one long twist.
19 Starting with one end, roll it inwards and tuck it under to create a wreath shape. Once you get to the other end, tuck it under your twist.
20 Place the twist into the smaller pan. Repeat with the larger portion of dough, roll it out to at least 18" x 12".
21 Cover the pans with plastic and set aside for at least 30-45 minutes to proof while the oven preheats. They're ready when they are almost doubled in size.
Bake
23 Once the oven is heated up and the layers have gotten nice and puffy it's time to bake. 
25 My oven will only fit one at a time so I baked the smaller one for 15 minutes, rotated it 180 degrees and then another 12-15 minutes. For the larger one it needs to be baked for 15 minutes, then rotate and bake for another 15-20 minutes.
24 If you're baking at the same time, they make take a bit longer. Be sure to bake until golden brown and not super wobbly.
26 Once baked, remove from the oven and place on a wire rack to cool slightly. It's ok if they sink a bit while cooling.
27 While they cool, make the frosting.
Vanilla Frosting
29 In a medium bowl, whisk together melted butter, lukewarm milk, vanilla, and powdered sugar.
30 If it is too thin, add more powdered sugar, if too thick add more milk. It should be pretty thick but still flowy.
31 Spoon the frosting onto each cinnamon roll tier. Then use the back of the spoon to spread the frosting out as needed.
To Stack
33 If you are baking and serving this cake at home, you can just place the smaller layer on top of the larger once they have both cooled. But, if the cake is being transported and needs to stand for a while you'll want to add in some supports.
34 Either way, do not stack until both layers have cooled.
35 To support the bottom layer, I cut three of these cake dowels to the same height. You want them to be exactly or just slightly shorter than where you are inserting them into the bottom tier.
36 I also ended up using a cardboard cake round to set the smaller cake on before placing it on top of the dowels and the bottom cake layer. I only had an 8" round so I trimmed it to just smaller than the top layer.