For the bread:
- 1 cup warm whole milk
- 4 tablespoons (57 grams) unsalted butter, melted
- 2 tablespoons (25 grams) granulated sugar
- 1 large egg plus 2 egg yolks, lightly beaten
- 2 1/4 teaspoons (1 envelope) instant yeast
- 4 cups (508 grams) bread flour
- 1 1/4 teaspoons fine salt
For the cinnamon swirl:
- 2 tablespoons unsalted butter, melted
- 1/4 cup (50 grams) granulated sugar
- 1/4 cup (50 grams) light brown sugar
- 2 tablespoons ground cinnamon
For the egg wash:
- 1 large egg
- 1 tablespoon milk
In the bowl of a stand mixer combine the milk, butter, sugar, egg, egg yolks, and yeast. Whisk to combine.
Add the flour and salt, attach the dough hook, and knead on low speed until a rough dough comes together. Increase to medium speed for about 5 minutes, or until it begins to become smooth and supple. Add more flour if the dough is unbearably sticky, just a couple tablespoons at a time. Transfer the dough to a lightly greased bowl, cover with plastic wrap and allow to rise until puffy and almost doubled in size, about 1 1/2 to 2 hours.
Punch the dough down. Transfer the dough to a lightly floured work surface and roll it into an 8 by 18-inch rectangle. With a pastry brush, brush all over with a thin layer of the melted butter. Combine the sugars and cinnamon and sprinkle over the buttered dough, leaving a 1-inch border on each long side.
Using a spray bottle, lightly spray the cinnamon sugar with water to moisten. This will prevent too much gaping between the swirls. Roll into a very tight log, pinching the ends to seal to prevent the filling from leaking out and bubbling over while baking.
Place the log seam side down in a lightly greased 9 by 5-inch loaf pan. Cover the pan loosely with lightly greased plastic wrap, and allow the bread to rise for about 1 hour, until it’s domed about 1-inch above the edge of the pan.
In a small bowl, beat the egg and milk. Brush all over the top of the dough.
Bake the bread in a preheated 350°F oven for 45 to 55 minutes, or until deeply golden brown. If using a glass or ceramic baking dish, drop oven temperature to 325°F and bake for about 1 hour. An instant-read thermometer should register at least 185°F at the center of the loaf. Tent the loaf loosely with foil if it begins to brown too much.
Remove the bread from the oven and allow it to cool completely in the pan on a wire rack before removing to slice. Store the bread in a plastic bag at room temperature for up to 5 days. You can also slice and freeze the bread for toast.