The dough recipe is adapted from https://www.lionsbread.com
3/4 cup buttermilk or milk at room temperature
1 stick unsalted butter melted
1 tablespoon sugar
2 teaspoons dry active yeast
3 cups unbleached ap flour
1/2 teaspoon baking soda
1 teaspoon kosher salt
6 tablespoons butter softened
3/4 cup sugar
1 tablespoon molasses
3 tablespoons cinnamon
pinch of kosher salt
1 teaspoon pure vanilla extract
Caramelized Onion Filling (enough for 1/2 of the dough)
one medium onion, diced and caramelized with a 1 tablespoon oil (it takes at least 25 minutes)
1/2 cup grated Parmesan cheese
1 teaspoon garlic powder
1/2 teaspoon onion powder
1/3 teaspoon freshly ground black pepper
1 tablespoon milk
NOTES: after you make the dough you can divide into 2 and make half with the cinnamon filling (using only a half of the filling recipe), and half with the onion filling. If you ended up making the whole cinnamon filling recipe, the extra cinnamon can be served on top of the baked rolls, or kept in the fridge to eat over toast!
Make the dough
In the bowl of a stand mixer fitted with the dough hook attachment, combine the buttermilk, dry active yeast, melted butter, egg, and brown sugar. Use a fork or small whisk to combine, dissolving the yeast. Turn the mixer on low, and add unbleached all purpose flour, baking soda, and kosher salt. Mix for 2-3 minutes, scraping the sides occasionally with a rubber spatula. Turn the mixer off, and cover the bowl with a clean kitchen towel, and let the dough rest for 5 minutes. Then, continue to mix/knead the dough on medium speed for 3-4 minutes, until the surface of the dough is smooth. Place the dough in a lightly oiled bowl, and cover with plastic wrap, beeswax wrap, or a clean kitchen towel, and let rise at room temperature for 1½-2 hours, or until the dough has doubled in size.
Make the Filling
In a small/medium mixing bowl, combine the softened butter, sugar, molasses, cinnamon, salt, and vanilla extract. Use a fork to mix until all of the ingredients are thoroughly combine, and you've formed a smooth paste consistency.
for the savory filling: mix all ingredients and make sure it has completely cooled down before using.
Spray a 9x13" pan with nonstick cooking spray or a 12 muffins pan, with liners Set aside.
Pour the risen dough out onto your floured work surface. Flour the top of the dough lightly. Use a rolling pin to roll the dough out to a 10x5" rectangle. Fold the dough in half lengthwise. Then fold it halfway again, so you have a square. Flour the top lightly, and use your rolling pin to press the dough down, and roll back out to a 10x5" rectangle. This creates more layers of butter and flakiness.
Pour the spiced butter filling mixture onto the dough. Use a small offset spatula to spread the filling evenly over the dough, leaving a 1/2" border around the edges. Roll up the dough tightly, lengthwise, to create a long log, then pinch the ends closed. Cut the dough in half in the center. Then cut each half into 6 equal pieces.
Place the rolls into the prepared baking pan. Cover the pan with plastic wrap, and let proof at rom temperature for 1-1½ hour until the rolls are puffy and risen. Preheat the oven to 350 degrees F. Remove the plastic wrap, brush with the egg wash and bake the rolls for 30-35 minutes for the pan, and 25 minutes for the muffins, until golden brown.