To prepare dough, dissolve yeast in warm water in a large bowl; let stand 5 minutes, add 1/4 cup sugar, 1/2 cup sour cream, 2 tbsp softened butter, salt and egg, and beat with a mixer on medium until smooth.
Lightly spoon flour into dry measuring cups and level with knife.
Add 2 cups flour to yeast mixture, beat till smooth.
Add 1 more cup flour and stir with wooden spoon till a dough forms.
Turn dough out onto a floured surface.
Knead until smooth and elastic (10 minutes), add enough remaining flour, 1 tbsp at a time to prevent dough from sticking to hands (dough will feel sticky).
Place dough in a large bowl coated with cooking spray, turning to coat top, cover and let rise ina warm place (85°) free from drafts, 1 hr and 15 minutes or until doubled in size (gently press with 2 fingers into dough, if indentation remains its ready).
Punch down, cover and let rest 5 minutes, divide in half, working with 1 portion at a time (cover the other).
Roll each portion into a 12-inch round on floured surface.
Brush each circle with 1 Tbsp melted butter.
Combine 3/4 cup sugar and the orange rind, sprinkle half of the mixture over each round.
Cut into 12 wedges, roll up each wedge tightly, starting at the wide end.
Place rolls, point side down, in a 13 x 9-inch baking pan coated with cooking spray/ Cover and let rise 25 minutes or until doubled in size.
Preheat oven to 350°.
Uncover and cook 20-25 minutes, or until golden brown.
While the rolls bake, prepare the glaze, combine 3/4 cup sugar, 1/4 cup butter and orange juice in a small saucepan, bring to a boil over medium heat, cook 2 minutes or until the sugar has dissolved, stirring, remove from heat and cool slightly.
Stir in the sour cream, drizzle the glaze over the hot rolls, lt stand 20 minutes before serving.
Keep any remaining rolls in the pan, cover with foil and store them in the refrigerator, to reheat, place foil-covered pan in a 300 degree oven for 15 minutes or until warm.
