Begin by adding your warmed almond milk and yeast to a large mixing bowl. Let sit for 3-5 minutes to make sure the yeast is activated. You will be able to tell if it's bubbling. If used instant yeast, you can skip the waiting period in this step as it’s only needed if using active dried yeast.
Next, add the sweet potato purée, sugar, melted vegan butter, and vanilla to the large mixing bowl and whisk together to combine.
Once mixed, gradually begin adding in your flour about ½-1 cup at a time. Also, add in the 1 tsp of salt at this time.
Once all the flour has been added in, knead the dough. If using a standing mixer, switch the attachment to the bread hook and knead for 5-10 minutes until elastic. If you are kneading by hand, knead on a well-floured surface for 10-15 minutes or until the dough is elastic and significantly less sticky. (Since the dough has sweet potato in it, it will be stickier than normal bun dough, but should firm up a lot during kneading).
Once the bread is ready, add it to a well oiled bowl for the first rise. I prefer to coat my bowl in olive oil, but any oil works here. The dough will be sticky so you may want to flour your hands before grabbing the dough.
Then, cover the bowl with plastic wrap or a towel, place in a warm place, and let rise 30 minutes- 1 hour until doubled in size. I like to test my dough by "poking" it with a finger. If it doesn't bounce back and stays indented, it is ready. It is also important to not “overproof” the dough as it can turn sour from the yeast turning the sugar into alcohol, so do not let the dough sit too long (I found over 1 hour is too long for this dough).