1. Pour water and milk into the mixing bowl, add yeast and stir it into the water.
2. Whisk the eggs with a fork and pour them in.
3. Mix whole grain flour, sugar, and salt and add it in.
4. Add the wheat flour and mix with the dough hook for about 5 minutes at medium-low speed.
5. Increase to medium speed and add a small lump of butter at a time until all is incorporated – I pinch it off the block with my fingers so it becomes soft enough to knead into the dough.
6. Increase the speed a bit and knead until the dough leaves the bottom and sides of the bowl.
7. Place a cloth over the dough and let it rest for 30 minutes.
8. Divide the dough into 15-18 equal parts (87 grams or 77 grams each).
9. Tighten the dough pieces and roll them round – if you want a slightly flatter burger bun, press them down on top.
10. Place the buns on a baking sheet with 2-3 cm space between them and let them rise under a cloth until they just touch each other.
11. Bake them in the oven at 185 degrees Celsius (365 degrees Fahrenheit) with convection for about 15 minutes – if you want sesame seeds on top, brush with egg and sprinkle the seeds before putting them in the oven.
12. Take them out and let them cool on a rack.
13. Make a burger.