0.5 cup unsalted butter – divided, plus more for pan
1 large egg – room temperature
1 tsp salt
3.75 cups all-purpose flour – divided, plus more for dusting
2 oranges – zested and juiced
2 cups powdered sugar
Instructions
Grease a 9x13-inch baking pan with a little butter; melt 0.25 cup of the unsalted butter and let cool slightly, leaving the remaining 0.25 cup to soften at room temperature.
Zest and juice the oranges; reserve 1 tbsp zest for the glaze and use the remaining zest for the filling. Reserve 4–6 tbsp juice for the glaze.
From the granulated sugar, set aside 0.5 cup for the filling and 1 tbsp for blooming the yeast; the rest will go into the dough.
Warm the whole milk to 105–110°F. Sprinkle the active dry yeast and the 1 tbsp reserved sugar over the milk, stir, and let stand until foamy, 5–10 minutes.
Whisk the large egg and salt into the foamy mixture, then whisk in the melted butter and the remaining sugar.
Add about 3.25 cups of the all-purpose flour and mix until a soft dough forms. Turn out and knead on a lightly floured surface, adding just enough of the remaining flour to prevent sticking, until smooth and elastic, 8–10 minutes.
Place the dough in a greased bowl, cover, and let rise in a warm spot until doubled in size, 60–90 minutes.
Make the filling: In a small bowl, mash the softened butter with the 0.5 cup reserved sugar and the remaining orange zest until evenly combined.
Punch down the dough and roll it into a 12×18-inch rectangle. Spread the filling evenly over the surface, leaving a 0.5-inch border on one long edge. Roll up tightly from the opposite long side and pinch the seam to seal.
Cut the log into 12 even pieces and arrange them cut side up in the prepared pan with a little space between. Cover and let rise until puffy and nearly doubled, 45–60 minutes.
Bake at 350°F until golden brown and the centers spring back lightly when touched or register about 190°F, 20–25 minutes.
Make the glaze: Whisk the powdered sugar with 4–6 tbsp reserved orange juice and the 1 tbsp reserved orange zest until thick but pourable; adjust with more juice as needed.
Cool the rolls in the pan for 10 minutes, then drizzle or spread the glaze over the warm rolls. Serve warm or at room temperature.