- For the dough, measure the flour, sugar, yeast and salt in the bowl of a stand mixer fitted with the hook attachment. Stir the hot water and milk together (the hot water and cold milk should result in a liquid of about 115°F/46°C). Add the milk mixture and the eggs to the bowl and start the mixer on low, letting it go for a minute or two until the dough is almost combined. Add the butter, a few pieces at a time, while the mixer is on. Increase the speed one level and continue to mix until the dough looks smooth (it will be very soft), about 6 minutes.
- Transfer the dough to an ungreased bowl, cover with plastic wrap and let sit on the counter for an hour. Refrigerate overnight (6 to 24 hours) so the dough firms up.
- For the filling, beat the butter by hand to smooth it out, then add the brown sugar and cinnamon, beating well.
- Grease a 9-inch (23 cm) springform pan. Turn the dough out onto a lightly floured surface and roll into a 12 × 18-inch (30 × 45 cm) rectangle about ½ inch (1 cm) thick. Spread the brown sugar filling over the dough.
- To make the giant spiral, cut the dough lengthwise into four strips. Start rolling up one of the strips from the short side. When you reach the end, overlap the end piece with the short end of the next strip of dough and continue rolling up into a spiral. Repeat with the last two pieces of dough—you should have a spiral about 7 inches (18 cm) across. Place this spiral into the pan and flatten the dough with the palm of your hand so that it almost reaches the edges of the pan. Cover the pan with a tea towel and let sit on the counter for about an hour, until the bun fills the pan—you will see that the centre pushes up a little when it rises.
- Preheat the oven to 375°F (190°C). Bake the bun for about 50 minutes, until a rich golden brown. Cool the bun in the pan on a rack for 30 minutes, then remove from the pan before glazing.
- For the glaze, whisk the icing sugar, milk and vanilla together until smooth. Use the whisk to drizzle the glaze over the giant cinnamon bun. Let the glaze set for 15 minutes before slicing into wedges to serve. The cinnamon bun is best enjoyed the day it is baked, but can be stored, well covered, on the counter for up to 2 days. It can also be sliced and toasted on low heat.
To dress up your cinnamon bun filling, feel free to sprinkle on 1 cup (150 g) raisins, 1 cup (100 g) walnut or pecan pieces, or even a grated apple over the cinnamon filling before rolling.
From Baking Day with Anna Olson, Appetite by Random House, 2020