Roll out crescent rolls into a square. Be sure all seams are together. Spread on Dijon mustard with a brush. Pile shredded Gouda in the center. Bring corners together and seal, then twist top to get a knot effect. Brush with melted margarine. Sprinkle with poppy or sesame seeds. Put in a greased pie plate and bake at 350 degrees for 15 minutes. Let cool for 5-10 minutes. Cut with a serrated knife.