In a stand mixer fitted with a dough hook or large mixing bowl, add the whole milk, sweet levain, egg, sugar, vanilla, pumpkin puree, all of the tangzhong, cinnamon and ginger.
All of the prepared tangzhong, ¾ (200g) cup sweet levain , 3 (50g) Tbsp whole milk, 2 (25g) Tbsp water, ¾ (175g) cup 100% pumpkin purée, ¼ (50g) cup granulated white sugar, 1 large egg, 1 tsp vanilla extract, 1½ tsp ground cinnamon, ¼ tsp ground ginger
Whisk ingredients together quickly, it's okay if it's lumpy.
Sourdough Discard Option: If you're making this recipe with discard and yeast, add the discard and instant yeast instead of the sweet levain to the wet ingredients and whisk in.
3/4 (200g) cup sourdough discard, 2¼ (7g) tsp instant yeast
Add your flour and salt into your wet ingredients.
4 (500g) cups all-purpose flour, 1½ (10g) tsp fine sea salt
Mix the dough on low until a shaggy dough forms, about 2-3 minutes. Scrape down the bowl if needed. If you're using your hands, knead the dough until it comes together.
This is a higher hydration dough from the pumpkin, so be aware it will be sticky!
Once the dough has come together, add the softened butter a tablespoon at a time mixing each tablespoon in until adding the next.
5 (65g) Tbsp unsalted butter
Use a dough scraper to scrape the edges of the bowl to make sure everything is getting mixed in.
Continue mixing the dough on medium-low (speed 2–3) for 8–10 minutes, until the dough is smooth, elastic, and tacky but not sticky.
Hand mixing directions: knead the dough until the butter has fully been incorporated, and the dough is smooth and tacky.
Mixing Notes: If kneading the dough in a mixer or if dough is very wet when mixing by hand, add an additional 25 grams (3 Tablespoons) of flour and mix into dough. Make sure to work flour in completely and assess if you need more flour.
Do not add more than 50 grams of flour at this stage, or you will lose the high hydration of the dough and end up with a dense donut.
If using a stand mixer, dough can become more warm and sticky and I have found kneading dough with my hand (perform a set of stretch and folds) for a minute after mixing in my stand mixer really helps bring the dough together.