Large egg yolks, room temperature. Do not SKIMP on the egg yolks! Or just do half the recipe!
Grams of unsalted butter (about 7 tbsp), room temperature and cut into about 7 pieces
ml of whole milk (about 6 tbsp + 2 tsp)
Grams active dry yeast (I used 2 packets of Red Star dry yeast). I have also successfully used 2 tsp of instant yeast (my favorite is Red Star Platinum Superior Baking Yeast)