Mix levain ingredients together and let sit covered at room temperature (around 75°F) for 4 hours.

On a plate, cut butter into small pieces to be used after dough is mixing later. Allow to come to room temperature while prepping dough.

In stand mixer with paddle attachment, add the following to the bowl: flour, pumpkin, milk, honey, water, salt, cinnamon, and levain.

On speed 1, mix for a few minutes until ingredients are all combined and there aren't any dry spots.

Switch to dough hook and mix on speed 2 for 5 minutes until dough is firm.

Let dough rest for 15 minutes to hydrate.

Butter should be warm enough to add. Turn mixer back on at speed 1 and add a couple pieces of butter at a time, allowing them to incorporate fully before adding more. This will take about 10-15 minutes total.

Transfer dough to bulk fermentation container and cover*.

30 minutes after the start of bulk fermentation, uncover dough and use wet hands and stretch and fold dough over itself, rotate container 90 degrees, repeating this twice. Cover.

Repeat stretch and fold set a second time about 30 minutes later, and cover again for remainder of bulk fermentation time (3-4 hours longer).

Dough should be smooth and strong and puffy now.

Butter or grease two 9x13 baking dishes.

Lightly flour dough, cutting board, and scale.

Gently pull out the dough onto floured work surface.

Divide dough into approximately 70 grams and gently shape into balls, placing into the greased pan. You can either eyeball or use a scale and divide your dough into 32 pieces.

Place 16 rolls in each pan. They will be touching.

You can bake the same day with a warm proof by covering and keeping it at room temperature in your kitchen for 3 hours.

For more flavour development, cold proof over night in plastic bag in the fridge and bake in the morning after taking out of the refrigerator for 4 or so hours for final proof.

Once they are fully proofed and puffed up to the edges, test with a gentle touch. Buns should be airy and soft. Proof a Preheat oven to 425°F and beat the egg with milk.

Remove from bag and lightly brush egg wash on all the buns. Add sesame seeds if desired.

Slide pans into oven, baking for 10 minutes.

Swap pans top to bottom and turn them each 180°. Reduce oven temperature to 350°F and bake for another 20 minutes until tops of rolls are golden.

Take out of oven and cool for at least 15 minutes before removing from the pan.

I like to cool for 30 more minutes before eating.