Prepare the yeast mixture: In a large mixing bowl (or the bowl of a stand mixer), combine the warm milk (ensure it's between 40-46°C / 105-115°F; too hot will kill the yeast, too cool won't activate it) with the active dry yeast and 1 tbsp (15g or 1/4 cup) of the granulated sugar. Stir gently to combine. Let it sit for 5-10 minutes until it becomes foamy and bubbly. This indicates the yeast is active.

Add wet ingredients: To the foamy yeast mixture, add the remaining granulated sugar (35g or 1/4 cup minus 1 tbsp), the softened unsalted butter (60g or 4 tbsp), and the room temperature eggs. Whisk everything together until well combined.

Add dry ingredients: Add the salt and about half of the all-purpose flour (225g or 1.75 cups) to the wet ingredients. Mix with a wooden spoon or the dough hook attachment of your stand mixer on low speed until just combined.

Knead the dough: Gradually add the remaining flour, about 1/4 cup (30g) at a time, mixing until a shaggy dough forms. If using a stand mixer, increase the speed to medium-low and knead for 8-10 minutes, or until the dough is smooth, elastic, and pulls away from the sides of the bowl. If kneading by hand on a lightly floured surface, it will take about 10-15 minutes. The dough should be soft and slightly sticky but manageable.

First rise: Lightly grease a clean large bowl with a little oil or cooking spray. Place the dough in the bowl, turning it once to coat the surface. Cover the bowl tightly with plastic wrap or a clean kitchen towel. Let the dough rise in a warm place for 1 to 1.5 hours, or until it has doubled in size. A good warm spot is an oven that has been turned off after being preheated briefly to about 38°C (100°F).

Prepare the cinnamon filling: While the dough is rising, in a small bowl, combine the packed light brown sugar (150g or 3/4 cup), ground cinnamon (15g or 2 tbsp), and the melted unsalted butter (50g or 3.5 tbsp). Mix until it forms a thick, spreadable paste.

Shape the dough: Once the dough has doubled, gently punch it down to release the air. Turn the dough out onto a lightly floured surface. Roll the dough into a large rectangle, approximately 30x40cm (12x16 inches) and about 0.6cm (1/4 inch) thick. Ensure the edges are relatively even.

Spread the filling: Evenly spread the prepared cinnamon-sugar mixture over the surface of the dough rectangle, leaving a small border (about 1.25cm or 1/2 inch) along one of the long edges. This will help seal the roll.

Roll the dough: Starting from the long edge opposite the clean border, tightly roll up the dough into a log. Pinch the seam firmly to seal it. You should have a long, even log.

Slice the log: Using a sharp knife or unflavored dental floss, cut the log into 12 equal slices, each about 2.5cm (1 inch) thick. If using floss, slide it under the log, cross the ends over the top, and pull to slice.

Second rise: Grease a 23x13cm (9x5 inch) loaf pan. Arrange the cinnamon swirl slices cut-side up in the prepared loaf pan, packing them snugly together. Cover the pan loosely with plastic wrap or a kitchen towel. Let the bread rise in a warm place for 45-60 minutes, or until puffy and nearly doubled in size.

Preheat oven and bake: While the bread is in its second rise, preheat your oven to 180°C (350°F). Once the bread has completed its second rise, remove the cover and place the loaf pan in the preheated oven.

Bake the bread: Bake for 30-40 minutes, or until the top is golden brown and the internal temperature reaches 90-93°C (195-200°F) when measured with an instant-read thermometer. If the top starts to brown too quickly, you can loosely tent it with aluminum foil.

Cool the bread: Remove the bread from the oven and let it cool in the pan on a wire rack for about 10-15 minutes. Then, carefully invert the bread onto the wire rack to cool completely.

Prepare optional glaze: While the bread cools, whisk together the powdered sugar (100g or 3/4 cup) and 1-2 tbsp (15-30ml) of milk or cream in a small bowl until smooth and drizzly. Add more liquid sparingly if needed to reach desired consistency.

Glaze and serve: Once the bread has cooled slightly or is completely cool, drizzle the glaze over the top. Let the glaze set for a few minutes before slicing and serving. This bread is delicious when toasted.