In a large bowl, dissolve yeast in warm water. Add 2 teaspoons sugar; let stand for 5 minutes. Add the milk, oil, salt, remaining sugar and 4 cups flour. Beat until smooth. Add enough flour to form a stiff dough.
Turn onto a floured surface; knead until smooth and elastic, about 6-8 minutes. Place in a greased bowl, turning once to grease top. Cover and let rise in a warm place until doubled, about 1-1/2 hours.
Punch dough down. Divide into four portions. Cover three pieces with plastic wrap. Shape one portion into 12 balls. To form knots, roll each ball into a 10-in. rope; tie into a knot. Tuck and pinch ends under. Repeat with remaining dough.
Place rolls on greased baking sheets; brush with butter. Cover and let rise until doubled, about 20-30 minutes.
To serve immediately, bake at 375° for 15-18 minutes. To freeze for later use, partially bake at 300° for 15 minutes. Cool and freeze.
To use frozen rolls: Reheat frozen rolls at 375° for 12-15 minutes or until browned.