In a stand mixer with a dough hook, add in ¼ cup of water and 2 ¼ teaspoons of active dry yeast. Let sit until the yeast is bubbly - about 5 minutes.
Add in the ½ cup of All-Purpose Flour, ⅓ cup Sugar, ¼ cup milk, 2 large eggs, 1 teaspoon of vanilla and 1 teaspoon of salt. Mix on low speed until completely combined and then gradually add in 2 - 2 ¼ cups of All-Purpose Flour. Mix for 1 minute or until the dough has come together.
Once mixed, let the dough stand for 15 minutes, then knead on medium-low speed for 5-7 minutes, until the dough is smooth, elastic and no longer sticks to hands.
Add in 6 tablespoons of unsalted butter that's very soft. Knead the butter into the dough until it's smooth and not slimy. Transfer to a large greased bowl and cover with a towel. Let it rise in a warm place until doubled in size, about 1 ½ hours.