1. Warm the milk to 110-115 degrees Fahrenheit and then transfer to a large mixing bowl. Sprinkle the yeast on top of the warm milk and then sprinkle the granulated sugar over the yeast. The yeast should begin to foam and become frothy. If after 5 minutes the yeast still does not start to foam or become frothy, throw out the milk mixture and start again with new yeast. Next, add the melted butter, egg, and egg yolk, vanilla extract, mashed sweet potato, cinnamon, ginger, nutmeg, and cardamom to the yeast mixture and whisk together until well combined.
2. Sift the flour and salt into the wet ingredients. Use a wooden spoon or rubber spatula to stir in the flour until a well combined dough forms, being sure to incorporate all of the flour from the sides of the bowl. You’ll know it’s time to move on to the next step once it becomes hard to stir. The dough will be thick and shaggy and still quite a bit sticky and that’s ok!
3. Turn the dough out onto a lightly floured surface and then use your hands to knead the dough for 8-10 minutes until it becomes elastic and can easily form into a smooth ball. The dough should feel slightly tacky but it should not stick to your hands or the kneading surface. If the dough is still too sticky after kneading for a few minutes, add 1 tablespoon of flour at a time and continue to knead the dough until it becomes a smooth, elastic ball.
4. Grease a clean, large bowl with one teaspoon of avocado oil and then transfer the ball of dough to the greased bowl. Cover the bowl with a tea towel and let the dough rise in a warm area (like the top of your oven/stovetop) for 1 – 1 1/2 hours or until the dough has doubled in size.
5. While the dough is rising, make the filling by combining the dark brown sugar, spices, and vanilla extract in a small bowl.
6. Once the dough has risen, punch it down to release the extra air and then transfer to a lightly floured surface. Shape the dough into the shape of a rough rectangle and then use a rolling pin to roll the dough out into a 20×16 rectangle that is roughly 1/4 inch thick.
7. Use an offset spatula or knife to spread the softened butter evenly over the dough and then sprinkle the filling mixture over the butter, being sure to cover all of the edges of the dough. Use your fingers to press the sugar mixture into the butter a bit.
8. Tightly roll up the dough, on the long side, and place the log seam side down. Pinch the seam a bit so the rolls don’t unravel. Use a sharp serrated knife or unflavored dental floss to cut the roll into 12 equally sized pieces. Place the cinnamon rolls in a 9×13 casserole dish, lined with parchment paper, evenly spaced apart. You should have 3 rows with 4 rolls per row.
9. Cover the casserole dish with a tea towel and let the cinnamon rolls rise for another 25-30 minutes or until they have almost doubled in size.
10. Bake the cinnamon rolls on the center rack at 350 degrees for 20-25 minutes or until the rolls are a light golden brown and sound hollow when tapped. Remove the cinnamon rolls from the oven and let cool for 10 minutes before icing.

Make the Brown Butter Cream Cheese Icing:

1. Add the diced butter to a small skillet or pot. Heat the skillet to medium heat. The butter will start to melt as the skillet heats up.
2. Allow the butter to bubble and “cook” until it begins to change from a bright yellow color to a golden brown color. Continually stir the butter as you see the foam start to dissipate and brown bits begin to form in the bottom of the pan. Cook and stir the butter until it is a golden brown color and has a nutty aroma.
3. Remove the butter from the heat and transfer to a heat safe dish. Transfer to the fridge to refrigerate until solid.
4. Add the cream cheese, solidified brown butter, and confectioner’s sugar to a mixing bowl. Use a hand mixer to mix the frosting until it is fluffy and the confectioner’s sugar is well incorporated without any lumps. Next, add in the orange juice, vanilla extract, and cinnamon. Mix on high again until well combined. Set aside until ready to use.