Actually, first we will start with heat treating the flour for the cookie dough, so it can cool. Preheat the oven to 300℉ and spread the flour over a cookie sheet. Bake for 8 minutes. Set aside to cool.
1 1/2 cup All-purpose flour
In a microwave safe bowl, heat the milk for 1 minute until heated to 110℉. Spread the yeast over the top of the milk and add a sprinkle of sugar. I don't stir it in. Let it sit for 10 minutes, the yeast will get bubbly and foamy.
1 cup Milk, 2 1/4 tsp Active dry yeast, Sprinkle of sugar
In a large bowl, add the flour, sugar, and salt. Add the milk/yeast, lightly beaten egg, and cubed butter.
1 Large egg, 3 1/2 cups All-purpose flour, 3 TBSP White granulated sugar, 1 tsp Salt, 1/2 cup Unsalted butter
Use a stand mixer with a dough hook, and mix on low until a dough starts to form. Switch to medium speed and mix for 5 minutes to knead the dough. *Making by hand instructions in recipe notes. The dough should be tacky feeling, but not stick to your hands. It should pass the window pane test: take a small piece of dough, spread it thinly up to a light, if you see light through it that means the gluten has activated.
Preheat the oven to 200℉. Spray a large mixing bowl with nonstick spray and place the dough ball in the bowl. Cover with a clean kitchen towel and place in the oven. Turn off the oven and crack open the door. Let it rise for 1 hour.