Combine pepper and salt, and rub evenly over tenderloin. Place on a lightly greased rack inside a roasting pan.
Bake at 450° for 20 to 25 minutes or until a meat thermometer inserted into thickest portion registers 160°. Let stand 10 minutes; thinly slice.
Combine yeast, sugar, and 3/4 cup warm water in a large bowl; let mixture stand 5 minutes
Add biscuit mix and next 4 ingredients to bowl, stirring until dry ingredients are moistened. Turn dough out onto a lightly floured surface.
Pat or roll dough to 1-inch thickness; cut with a 2-inch round cutter. Place biscuits on a lightly greased baking sheet; place a pecan half in center of each biscuit.
Bake at 425° for 20 to 25 minutes or until lightly browned. Split biscuits; serve pork in biscuits with mustard.