Line a 9 X 9-inch square pan with foil, leaving a 2-inch overhang on two sides. Lightly butter foil & a wooden spoon. In a large bowl, combine rice krispies, flax flakes, pumpkin seeds,flax seeds & salt. In a large pot, melt butter; add marshmallows & stir with wooden spoon until marshmallows have completely melted. Stir in vanilla then add rice krispie mixture & QUICKLY combine well.