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.

In a small/medium mixing bowl, combine the softened butter, brown sugar, hawaij, 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.

In a small mixing bowl, combine the powdered sugar, instant coffee, cream, and kosher salt. Use a whisk to combine until the glaze is perfectly smooth. If you want a thicker consistency, add less cream. If you want the glaze a bit thinner, feel free to add more cream 1 teaspoon at a time (a little goes a long way!)

Spray a 9x13" pan with nonstick cooking spray. 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. Use a long piece of (unflavored) dental floss to cut the dough in half in the center, by running the floss under the log and bringing the ends up, crossing them to slice down through the dough. Then cut each half into 5 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, and bake the sweet rolls for 30-35 minutes until golden brown. Let the Hawaij Spice Rolls cool for 5-7 minutes. Then pour the coffee glaze over the top.