Preheat oven to 350 degrees F. Grease a 13x9x2-inch baking pan. Line with waxed paper or parchment paper; set pan aside.
In a medium bowl, combine pecans, brown sugar, butter, vanilla, and cinnamon. Spread mixture in the bottom of the prepared pan (mixture will not completely cover bottom of pan). Place rolls, top sides down, in pan.
Cover buns with foil. Bake about 20 minutes or until heated through and gooey. Invert onto a serving platter; remove paper.