Combine yeast and 1 tsp sugar in small bowl. Add warmed water, stir until yeast is dissolved and let it sit until it begins to form bubbles.
In large bowl or bowl of a stand mixer, combine ½ c. softened butter, remaining sugar and salt.
Using stir setting on mixer or using a wooden spoon, add yeast mixture, warmed milk and beaten eggs.
Slowly add in 2 cups of flour; stir 2 minutes or until smooth. Add in remaining 2 and ½ cups of flour, 1 cup a time until a soft dough is formed. The dough will be slightly sticky; add additional ½ cup of flour if dough is sticking too much to sides of bowl and spoon/mixer attachment.
Sprinkle surface of counter with flour and flour hands. Turn out dough onto floured surface, and knead only slightly (fold dough only 3-4 times), enough to form a ball of dough.
Place in a greased bowl, cover and place in a warm (but not hot) area. Allow to rise until double in size, about 1 hour. If risen dough is pressed down, the indentation should hold its shape.
Split dough into 3 even portions. Roll each portion out onto floured surface, using floured rolling pin into a 9” circle.
Using pastry brush, brush rolled dough with melted butter.
Using pastry wheel or pizza cutter, cut each circle into 4 large wedges. Cut each larger wedge into 3 smaller wedges, for a total of 12 wedges.
Starting with wide end, roll each wedge and tuck the tip on the bottom side of dough.
Place each butterhorn on lined cookie sheet (1dozen per cookie sheet).
Allow butterhorns to rise to double in size, about 1 hour.
Preheat oven to 350°F. Bake rolls 12-15 minutes, or until lightly golden brown. Brush hot rolls with any remaining butter that has been melted.