Cinnamon rolls with marshmallow glaze

For the dough

• bread flour, about two cups, 250g (AP flour is fine, but I like 00 bread flour for this)
• 1/3 cup (80mL) milk
• 1 packet (7g, 2.25 teaspoons) yeast (you could use half that)
• 2 tablespoons (30g) butter
• 1/4 cup (50g) sugar
• 1 egg
• half a teaspoon (3-4g) salt
• small glug of vanilla

For the filling

• 1/3 cup (65g) brown sugar (or white sugar with a glug of molasses, which is the same thing)
• small pinch of salt
• melted butter (you'll only need a little for the filling, but it's nice to have extra for other steps, so I'd melt a couple tablespoons)
• 1 tablespoon (8g) ground cinnamon (that's a lot — you could use less)

For the marshmallow glaze

• 1 egg white (leftover from the dough)
• 1/3 cup sugar (65g)
• a squeeze of corn syrup, honey, or any other syrup that isn't primarily sucrose
• vanilla
• 1 tablespoon (15g) butter

1. Warm the milk to body temperature, perhaps with a small pinch of sugar to further feed the yeast. Stir in the yeast and let bloom for a few minutes until frothy.
2. Melt the butter and stir in the sugar to cool it back down. Separate the egg, reserve the white for the glaze, and put the yolk in with the sugar and butter. (If making a full dozen rolls you could just use one whole egg.) Add the salt and vanilla to the butter mixture and stir smooth.
3. Stir as much flour as you can easily stir into the milk mixture with a spoon (it was a little less than a cup for me), and do the same with the butter mixture (mine took maybe 2/3 of a cup). Cover and let sit for about a half hour until the milk dough has puffed up a lot.
4. Knead the two doughs together until homogenous, dusting on additional flour as needed until you get a reasonably smooth dough that's just a little sticky. Cover and let rise until doubled, about 2 hours.
5. While you're waiting, you can mix up the filling ingredients. Be careful to add only enough melted butter to get a damp sand consistency — too much butter and the filling will melt out in the oven.
6. Transfer the risen dough to a board, dust with flour and roll out into a rectangle about a foot (30 cm) wide. Roll the bottom long end very thin — this will be the flap you use to seal the roll. Brush the surface with melted butter, avoiding that flat at the bottom. Pat on the filling as evenly as possible, again avoiding the bottom flap.
7. Smear some water on the bottom flap to serve as glue, then roll it up, starting from the thicker long end. Don't roll too tightly. Position the seam on the bottom of the roll, and maybe coat it with melted butter if you have some left. At this point you could cover and refrigerate the roll until later.
8. Trim off and discard the ends of the roll, then slice about 1.5 inches (4 cm) thick. Gently transfer the rolls to a parchment-lined baking sheet, cut-side-up. If you have time, cover them and let them proof one more time, about a half hour (definitely make time for this if you sliced the rolls straight from the refrigerator).
9. Bake at 400ºF/200ºC, convection if you have it, until just starting to go golden brown around the edges, 10-15 minutes.
10. While you're waiting, you can make the frosting. Whisk the egg white, sugar and syrup together in a saucepan over moderate heat. Whisk continuously until the eggs cook and you get a mayonnaise-like consistency. Kill the heat and whisk the butter as it slowly melts in. Whisk in a splash of vanilla and you're done.
11. Wait for the rolls cool and solidify for a few minutes before topping with the glaze — I just like to dunk the whole top of the roll straight into the pot.