Set the oven to warm or alternately as low as you can set it if you don’t have a warm option, about 170°. Lightly spray a 9x13 pan with pan spray and set it aside.
In the bowl of your mixer whisk together the flour, sugar, yeast, and salt.
In another bowl combine the warm milk and 4 tablespoons of melted butter. Using the dough hook on low, slowly add the liquid to the dry ingredients. Knead the dough for about 4 minutes or so, until it is smooth and elastic. If the dough is still very sticky, add more flour 1-2 tablespoons at a time.
Once you have achieved a smooth dough, cover the bowl and let rest for about 5-10 minutes.
Once the dough has rested, turn it out onto a lightly floured surface and divide the dough as evenly as you can into 15 pieces. I like to use a kitchen scale so I can get them equal in size. Weigh the whole ball of dough in grams and then divide it by 15. That’s the weight each roll should be. Shape each piece into a ball and pinch the dough together on the bottom.
Place the dough balls into the baking pan and use your fingers to rub a little bit of water over the tops of the balls so they don’t dry out while baking. Transfer to the warm oven and let rise for 20 minutes, or up to 30 minutes if they have not doubled in size after 20. I find it can be helpful to use a spray bottle to spray the bottom of the oven to create steam to help the rolls rise faster.
Remove the risen rolls from the oven and bump the heat up to 375°. As soon as the oven has preheated, bake the rolls for 16-18 minutes, until the tops are golden brown. Brush with melted butter as soon as they come out of the oven.