Spray a 9x13x2-inch baking pan with cooking spray.
In a large bowl, mix together the flour, sugar, and yeast; set aside.
In a small pot (I use a 1-quart pot), melt 2 tablespoons of the butter over low heat.
When the butter has melted, add the milk, water and salt to the pot. Continue heating over low heat, stirring occasionally, until the mixture reaches a temperature between 120°F and 130°F (I aim for 120°F; this will happen rather quickly, so don't walk away). Note: If your milk mixture gets too hot, just allow it to cool back down to the proper temperature and then proceed with the recipe (pouring it out of the pot into a measuring cup or bowl can help cool it down faster).
Add the milk mixture to the flour mixture; mix until a slightly loose and sticky dough forms.
Remove the dough from the bowl to a floured surface. Sprinkle the top of the dough with flour (about 2 tablespoons).
Knead the dough by hand for 5 minutes or until it it smooth and elastic. As you go, add flour, a little bit at a time as needed, just until the dough is no longer sticky. To knead dough: Push the dough down and away from you with the heel of your hand. Grab the edge of the dough that's farthest away from you and fold it over in half towards you. Push the dough down and away and fold in half. Keep repeating this process, occasionally turning the dough 45 degrees.
Lightly spray the bowl you mixed the dough in with cooking spray (I don't find it necessary to clean out the bowl first). Form the dough into a ball and place it in the bowl.
Cover the bowl with plastic wrap or a clean kitchen towel and let it rise for 15 minutes in a warm place that is free from drafts.
While the dough is rising, turn the oven on and start it preheating to 400°F.
Gently punch down the dough and divide it into 15 equally-sized piecesNote: You can eyeball it, but the easiest way to do this is to weigh the whole ball of dough on a kitchen scale (I use grams) and then divide it by 15 to determine how much each ball should weigh. I have made these rolls many times, and it always works out that each ball should weigh somewhere between 67 and 69 grams. Roll each piece of dough into a smooth ball, then pinch together any open seams on the bottom of the ball.Note: Don't use any additional flour at this point. Form the balls right on your clean work surface; the dough shouldn't stick. Adding more flour can cause your rolls to be tough and dense.To form the balls, loosely cup your hand over the dough and roll it around in a circular motion until it forms a smooth ball.
Place the balls in the prepared pan, seam side down, in 5 rows of 3.
Cover the pan with plastic wrap or a clean kitchen towel and let rise for 20 minutes in a warm place that is free from drafts. Remove the plastic wrap or towel from the pan.
Bake on the middle rack of the oven for 18 to 20 minutes or until cooked through and the tops are lightly golden brown.
Remove the pan from the oven and immediately brush the tops of the rolls with the melted butter.
Remove the rolls from the pan to a wire rack and allow to cool slightly.
Best when served still slightly warm from the oven!