Preheat oven to 425 degrees F. Spray a 9-inch cake pan with nonstick cooking spray.
Combine self-rising flour, sugar and salt. Work shortening in with your fingers until there are no large lumps. Stir in cream, then buttermilk, until it resembles cottage cheese. (Very sticky) Add more buttermilk, if needed.
Spread all-purpose flour in shallow pan. Scoop dough (use a #30) into flour, leaving space between each. Coat with flour, gently shape into a round, shaking off excess flour. Place biscuit into prepared pan, smooched up against its neighbor. Continue scooping and shaping.
Bake until lightly browned, 20 to 25 minutes. Brush with melted butter, invert onto plate, then back onto another. Cut biscuits to serve.