Pro-tip: For the best results, be sure to use a kitchen scale for precise measurements.

MAKE THE DOUGH:

1. Heat the butter and milk in a small saucepan on the stove or in a small bowl in the microwave until warm, but not hot.

   If the liquid is too hot (hotter than 120 degrees F), it can kill the sourdough starter. I like to heat and then cool slightly before adding to the dough. 
   240 grams warm milk, 57 grams unsalted butter
2. Meanwhile, add the active starter, egg, egg yolk, and sugar to the bowl of a stand mixer with a paddle attachment. Mix on low speed until combined, then gradually add the warm milk and melted butter mixture.

   This can also be done by hand. Increase the knead time to 15-18 minutes.
   200 grams active sourdough starter, 24 grams sugar, 1 egg, 1 egg yolk
3. To the wet ingredients, add the bread flour and salt and mix again on low speed. Stop to scrap the sides of the bowl to incorporate all the dry ingredients and then continue to mix on low for 1-2 minutes.
   500 grams bread flour, 11 grams salt
4. The dough will look thick and sticky, like a cake batter. Cover with plastic wrap or a clean kitchen towel, and allow the dough to rest for 30 minutes. This allows the gluten to rest before kneading.

KNEAD:

1. After 30 minutes, remove the cover and knead the dough with the dough hook attachment at medium speed for 10 – 15 minutes.

   You’ll know the dough has been kneaded completely when it is smooth and shiny. The dough will completely pull away from the sides of the bowl when it is being kneaded, tacky, not sticky, to the touch, and it will pass the windowpane test.

   This means when you stretch a small section of dough into a thin film, the light will be able to pass through without the dough tearing. If this is accomplished, the dough has been properly kneaded.
2. Remove the dough and place it in a lightly greased straight-edge bowl. I like to use butter or olive oil. Cover it again.

   I love using this straight-edge bowl because it allows me to clearly see when the dough is done rising.

BULK FERMENTATION:

1. Place the dough in a warm place in your kitchen and allow the dough to at least double in size. 

   In my 70 degree F kitchen, the first proof should take about 3-4 hours. The bulk fermentation time greatly depends on the temperature of your kitchen. If you have a colder kitchen, the rise time will take longer. If your kitchen runs warm, the first rise will take less time.

SHAPE:

1. Once the dough has at least doubled in size, punch the top of the dough to remove all the air bubbles. Then, place the dough on a clean work surface.
2. Gently stretch the dough into a rough rectangle shape. With a bench scraper or serrated knife, cut the dough into 8 equal pieces for large burger buns (about 130g each) or 10 standard sized burger buns (about 106g each).
3. Pull the corners of the dough towards the center, flip, and then roll each piece of dough into a round, tight ball. Place the shaped buns on a baking sheet lined with parchment paper. Repeat until all the rolls are shaped. 
4. Once shaped, cover the shaped buns with a plastic cover or plastic wrap, and let the dough rest for its second rise.

   In my 70 degree F kitchen, the second rise took about 1-2 hours. You will know the final proof is complete when the burger buns have grown and look puffy.
5. Not ready to bake these in the same day? No worries! See directions in the Notes section below.

BAKE:

1. Preheat the oven to 375 degrees F.
2. In a small bowl, whisk together an egg and a splash of water, then brush the top of each bun with the egg wash with a pastry brush. This will help them to get that lovely golden brown color. Top with sesame seeds, if desired.
   egg wash
3. Bake for 20-25 mins minutes or until the homemade Sourdough Burger Buns are golden brown. I like to check the buns around 15 minutes.

   If they are starting to brown too quickly, cover the buns with aluminum foil and continue to bake. Completely cooked buns will have an internal temperature is 190 degrees F.
4. Remove the Sourdough Burger Buns and let them come to room temperature before slicing and topping them with your meat and toppings of choice!