In a small bowl, mix warm milk, yeast, and 1 tbsp sugar. Let sit for 10 minutes until frothy. If it doesn’t foam, the yeast isn’t active, and you’ll need to start over.
Preheat your oven to the warm setting or 170°F (then turn it off).
In a stand mixer, add 3 ½ cups flour, melted butter, vanilla, sugar, and salt. Mix on low speed.
Slowly add in the yeast mixture while mixing.
Add eggs one at a time, ensuring they are fully incorporated.
Knead on speed 4 for 5 minutes (or by hand for 6 minutes on a floured surface). The dough should be smooth and slightly elastic. If too sticky, add a little more flour, up to ¼ cup.
Grease a bowl with oil, place the dough inside, and cover with a kitchen towel or plastic wrap.
Let it rise in a warm area for 1 hour, or place it near a cracked oven door.