Combine warm water, yeast and sugar in a small measuring cup or bowl. Let sit 5 minutes or until frothy.
Using a large mixing bowl and fitted with flat beater combine yeast mixture, butter salt, egg and 2 cups flour. Mix together. Once fully combined switch to dough hook and scrape down sides of the bowl. Increase speed to medium. After 2 minutes, add additional 2 cups of flour.
Knead for another 3-5 minutes or until dough comes together and is smooth. It should slap sides of the bowl and stick to the bottom.
Cover the bowl with plastic wrap and let rise in a warm place until doubled in volume, about 20 -30 minutes.
Lightly flour a smooth work surface. Plop dough down and gently flatten to a ½ inch or so rectangle. Divide into 20 equal pieces using a pizza cutter or dough scraper.
Roll each piece into a smooth round ball. Use the palm of your hand to roll gently until it pulls together.
Arrange dough balls in a lightly greased 9 x 13 pan and cover with a kitchen towel. Meanwhile, preheat oven to 400 degrees.
Let rolls rise until doubled, about 20 minutes. Brush with melted butter.
Bake for 15 minutes or until golden brown.