Caramelized Onion Stuffed Parmesan Pull-Apart Bread

Directions

1. Pour the water into the bowl of a stand mixer fitted with the dough hook. Sprinkle the yeast over the water and mix with a small spatula to combine. Let sit for 5 minutes.
2. In a small saucepan, heat the milk to about 110°F/45°C over medium-low heat (you can also do this in a liquid measuring cup in the microwave, if you prefer).
3. Add the flour, parmesan, dry milk, sugar, onion powder, salt, and paprika to the mixer bowl, then add the warm milk, egg, butter, and sour cream (or yogurt/crème fraîche), and mix on low speed for 4 minutes, or until a soft dough comes together around the dough hook.
4. Scrape the bowl well, then mix on medium speed for about 3 minutes more, until the dough is very smooth. Transfer the dough to a medium bowl lightly greased with neutral oil or nonstick spray. Use both hands to gently turn the dough around so it’s coated on all sides, then gently tuck the dough under itself a few times to slightly round it. Cover the bowl with plastic wrap or a clean kitchen towel, and let the dough rise for 45 minutes to1 hour, until visibly puffy and almost double in size.
5. While the dough rises, prepare the filling and finishing ingredients. In a large sauté pan, melt 2 tablespoons (28 grams) unsalted butter with the olive oil over medium heat. Add the onions and toss until well coated. Season with salt and pepper, and reduce the heat to medium-low.
6. Cook the onions until they are evenly and deeply caramelized, 40 to 45 minutes. Transfer the onions to a small food processor or blender and purée until smooth. Add the cream cheese and parmesan and blend until evenly combined.
7. Grease a 9x9-inch (23x23 cm) pan lightly with nonstick spray. Divide the dough into 25 even pieces (about 35 grams each), and round each piece into a ball. Cover the dough on your work surface with a clean kitchen towel for 10 to 15 minutes to rest. Working with one piece of dough at a time, roll out a ball of dough to ¼ inch thick (about 3 inches/8 cm wide). Spread 2 heaping teaspoons of filling evenly over the surface of the dough from edge to edge.
8. Fold the dough in half, leaving the edges unsealed, then fold in half again. The piece of dough will now resemble an unsealed fortune cookie, with the filling visible along one side, and the other sides neatly folded. Place the filled and shaped dough, with the filling facing upward, in the prepared baking pan. Repeat step 7 with the remaining dough and filling, and continue placing the pieces in the baking dish in rows (5x5 inside the pan).
9. Cover the dough with greased plastic wrap, and let rise until the dough looks visibly puffy, 45 minutes to1 hour. Towards the end of rise time, heat the oven to 350°F/175°C with an oven rack in the center.
10. When the dough has risen, brush the butter over the surface of the dough—being very generous and using it all. Garnish the surface with sesame seeds. Bake until deeply golden brown on the tallest portions of the dough (it may still be blond in some of the shorter portions), 40 to 45 minutes.
11. Cool in the pan for 10 minutes, then unmold onto a serving platter and serve immediately while warm.