Spray a 12-cup muffin tin with nonstick spray and set aside.
Place the milk, sugar, yeast, flour, egg yolks, and salt in the bowl of a stand mixer fitted with the paddle attachment. Combine on low speed for 1 minute. Change the paddle attachment to the dough hook and rest the dough for 10 to 15 minutes.
Add 4 tablespoons of the butter and mix on low speed. Increase the speed to medium and mix until the dough pulls away from the sides of the bowl and you are able to gently pull the dough into a thin sheet that light will pass through, about 8 minutes.
Turn the dough out onto a lightly floured work surface and shape with your hands to form a large ball. Return the dough to the bowl, cover with plastic wrap, and set aside in a warm, dry place to rise until doubled in size, about 1 hour.
Remove the dough from the bowl and roll into a 12-by-12-inch square, about 1/2-inch thick. Melt the remaining 1 tablespoon butter and brush onto the top of the dough.
Use a pizza cutter to cut the dough into 12 (12-by-1-inch) strips. Stack the strips into 2 stacks of 6 strips each. Lay the stacks on their sides and cut each stack into 6 (2-inch wide) pieces. Lay each piece on its side in a prepared muffin tin cup. Cover with plastic wrap and set aside in a warm, dry place to rise until doubled in size, 30 to 40 minutes.
Heat oven to 400ºF.
Remove the plastic wrap and bake until the rolls reach an internal temperature of 200ºF, 8 to 10 minutes. Rotate the pan halfway through baking.
Remove the muffin tin to a cooling rack and cool for 2 to 3 minutes before serving.