In large mixing bowl, dissolve 1 (1/4 oz.) pkg dry active instant yeast in 1/4 cup warm water, and a pinch of sugar from the 1/4 cup granulated sugar and let sit until bubbly.
Add in remaining 1/4 cup granulated sugar, 1 teaspoon salt, 2 large eggs,1/2 cup full-fat sour cream, 1 teaspoon orange zest and 6 Tablespoons unsalted butter , melted.
Gradually add in 2 cups of the 3 1/2 cups all-purpose flour; beat until smooth, about 2 minutes.
Add in remaining flour, turn out onto a floured surface and knead dough 15 times. Place in greased mixing bowl; cover and let rise in a warm (but not hot) place for at least 1 hour, or until doubled in size.
Punch down dough, divide in half. Using rolling pin, roll out into a rentable about 10" in length and about 3" in height. Brush each portion with 1/2 of the 2 Tablespoons unsalted butter using pastry brush and sprinkle with half the 3/4 cup granulated sugar and half the 2 Tablespoons orange zest on the dough.
Roll the dough up and seal edges. Cut rolls about 1" in length; place 3 rolls per row into prepared baking pans (1 dozen in 9"x13" pan and remaining rolls into the smaller 8" x 8" pan).
Cover pans and allow to rise in a warm (but not hot) place at least one hour, or until doubled in size.
Uncover rolls and bake @ 350°F, 20-25 minutes or until lightly golden brown (or if using an instant read thermometer, reaching 190°F).