Heat your whole milk in the microwave until it reaches 115 degrees. Stir in the sugar, vanilla extract, and the yeast. Let the mixture sit and bloom for 5-10 minutes, or until it's bubbly and frothy. In a large bowl, or the bowl of a stand mixer, stir together the eggs and soft butter- it will be a bit lumpy, but that's ok! Add the yeast mixture into the egg mixture, and stir to combine. Add in 3 cups of flour and the salt, and knead together until a dough forms, using the dough hook on a stand mixer. If the dough is super sticky and wet still, add a few more tablespoons of flour until it's pulling away from the sides of the bowl. It should be very soft still, but won't stick to your fingers. Knead the dough for 5-8 minutes, or until it's very elastic and smooth. Place the dough back in your bowl and cover. Let the dough rise until it's risen by about 1/3 in size, which takes about 30-45 minutes for me.