To melted butter, add flour, oats, sugar, spice and pecans. Mix until well combined but crumbly. Place on parchment paper lined baking sheet. Bake in preheated 400 degree oven for 15 minutes, stirring once. Cool and crumble completely. Place 3/4 of the crumbs in the bottom of a 9×13-inch pan, lightly greased with no-stick spray. Pour 1/4 to 1/2 of the butterscotch sauce on top. Add a THICK layer of ice cream. (May have to indulge in more than a pint!) Place the remaining crumbs on top, then dribble the rest of the sauce over the top. Cover the pan with aluminum foil and place in freezer to harden. Store in the freezer until ready to serve.