1. Arrange frozen biscuits, with sides touching, in 3 rows of 4 biscuits on a lightly floured surface. Let stand 30 to 45 minutes or until biscuits are thawed but still cool to the touch.
2. Sprinkle thawed biscuits lightly with flour. Press biscuit edges together, and pat to form a 10- x 12-inch rectangle of dough; spread evenly with softened butter. Stir together brown sugar and cinnamon; sprinkle evenly over butter. Sprinkle raisins and pecans evenly over brown sugar mixture.
3. Roll up, starting at one long end; cut into 12 (about 1-inch-thick) slices. Place rolls into a lightly greased 10-inch cast-iron skillet, 10-inch round pan, or 9-inch square pan.
4. Bake at 375° for 35 to 40 minutes or until center rolls are golden brown and done; cool slightly.
5. Stir together 1 cup powdered sugar, 3 Tbsp. milk, and 1/2 tsp. vanilla; drizzle evenly over rolls.