Ingredients:

For the dough:

1⅛ teaspoons (3.5g) instant yeast

3 tablespoons (35g) granulated sugar

¼ cup (75g) heavy whipping cream, warmed to 105-115°F 

½ cup (125g) milk, warmed to 105-115°F 

1 (50g) large egg, at room temperature

2 cups (262g) Trailblazer flour

1 teaspoon (5.2g) fine sea salt

Optional: ½ cup (65g) onions, in small dice

For the egg wash:

1 egg yolk

Pinch of salt

1 teaspoon water

Optional: white sesame seeds, as needed, for the topping

Instructions:

1. Combine instant yeast and granulated sugar in a bowl of an electric stand mixer.
2. Warm up the cream and milk and add them into the yeast and sugar, whisking while pouring. Mix until the sugar and yeast have dissolved. 
3. Add the egg and continue to whisk until well combined. 
4. Add the flour to the bowl, fit your mixer with a dough hook attachment, and begin mixing on medium speed.
5. Once most of the liquid has absorbed into the dough, add the salt.
6. Mix on medium high speed for a total of about 10 minutes, scraping down the sides of the bowl as you mix* (see Baker’s Notes). You can use a rubber spatula or dough scraper.
7. Prepare a lightly oiled bowl. 
8. Once the dough is elastic and well mixed, using oiled or wet hands, remove the dough from the mixing bowl, shape it into a rough ball, and place it into the prepared bowl.
9. Cover with a tea towel or plastic wrap and allow to proof at room temperature for about 1- 1½ hours or until doubled in size.
10. Prepare a clean work surface and dust generously with flour.
11. Punch down the dough and roll it out of the bowl and onto the floured surface. 
12. Divide the dough into 6 equal-sized portions, about 90g each. If adding onions to your dough, the weight of each portion will be about 100g.
13. Rest the dough, uncovered, for 10 minutes. This will allow the dough to not be as sticky but will also allow the gluten to relax for easier shaping.
14. Line a baking tray with a sheet of parchment** (see Baker’s Notes) or silpat.
15. Shape each piece of dough into a light ball. Be sure to punch out all the air while shaping to prevent large air bubbles in the dough. This dough is quite sticky, so don't be shy to use a bit of extra flour while shaping.
16. After all the dough balls have been shaped, place them on the prepared tray about 2 inches apart so they do not touch as they expand or bake.
17. Сover with a flour-dusted tea towel or plastic wrap and allow to proof again for about 45 minutes. 
18. After the buns have almost doubled in size again, using a rolling pin, lightly roll the dough down to flatten the tops. You can keep the plastic wrap or tea towel on when you’re doing this*** (see Baker’s Notes).
19. Preheat the oven to 350°F with a rack positioned in the center of the oven.
20. Allow the buns to proof for another 15 minutes after you rolled out the tops.
21. While the oven is warming and the dough is on its final proof, start preparing the egg wash**** (see Bake’s Notes).
22. Once the dough has rested and started to puff up again, apply the egg wash with a brush, being sure to cover the sides and top evenly.
23. If adding sesame seeds, sprinkle a few on top. You can also omit this step, if you prefer your hamburger buns plain. 
24. Bake in the center of the oven for 12 minutes. Rotate the tray 180° and bake for another 8 minutes or until evenly browned. 
25. Transfer to a cooking rack and allow to cool at room temperature for about 15 minutes before slicing into the buns.