This is from the package for the Paskesz marshmallows, and I'm putting it here for convenience.

Time: 20 minutes cook, 1 hour (?) cool. Uses 9x13 pan (half-sheet OK) and makes 24 2x2-inch squares.

1/3 stick margarine

1 8oz bag marshmellows

4 cups rice cereal

Melt margarine in large saucepan over low heat. Add marshmallows and stir constantly until completely melted. Add crisp rice cereal and stir until well coated. Using a greased spatula or waxed paper, press mixture evenly into greased 9x13 pan. When cool, cut into squares. Makes 24 2x2 squares.

Typists note: How do you get 2x2 squares from a 9x13 pan? An 8x12 pan would give 4 on the short axis and 6 on the long axis, and 4x6=24, so a 9x13 has an extra inch on both axes for the cook.