Add active dry yeast, warm water, and sugar to a large bowl and let it sit for 5-10 minutes until the yeast foams up and becomes active.
Add bread flour, sourdough starter, salt, and activated yeast mixture to a kitchen stand mixer with the dough hook. Let is knead on medium speed 6-8 minutes. The dough should be tacky and form into a ball.
Grease a large bowl with avocado oil and place the dough inside making sure both the bottom and top of the dough are brushed with oil. Cover it and let it rest in a warm place for 2 hours.
Once dough has rested, roll it into a long rectangle, and cut 8 pieces roughly about the same size.
Pinch the ends of each of the 8 pieces of dough, and shape into a ball. Gently roll on the counter for about 30 seconds to get the dough into a smooth shape. Next, cover with a clean dish towel, and allow the dough to rest on the counter for 15-30 minutes.
Bring a large pot of water to a boil. Once it boils, add 1 tbsp of molasses. Next preheat your oven to 400℉. * (If you want to add toppings, gather them all now so you have it ready.)
Now poke a hole in the center of each dough with your finger and pull the hole out to enlarge it creating a donut shape.
Once the water boils, gently add the dough in and boil for 30-45 seconds on each side. *Don't overcrowd the pot with too many donuts, do a few at a time and work quickly.
Place all the boiled donuts onto a large baking sheet lined with parchment paper. Add desired toppings or leave plain.
Bake at 400℉ for 15-20 minutes, or until the top of the donuts look golden brown. Allow it to cool for 10-15 minutes before eating. Enjoy!
