1/4 cup dairy-free chocolate chips or 4 ounces of chopped chocolate bar (I used an Enjoy Life Dark chocolate bar today).
Prepare a square baking pan, 9 x 9 or 8 x 8, doesn’t matter. Glass, Pyrex, metal, all ok. Spray with cooking spray. My cake pan is a nice Sur La Table non-stick pan, and I don’t want to cut the treats in the pan and ruin the coating. So I make a “Parchment Belt” to lift the square out when cool. I fold a sheet of parchment paper in the bottom, letting the edges hang over the sides. That way I can lift the block of treats out before cutting.
In a large microwave safe bowl, heat the margarine and marshmallows, 30 seconds at a time, until they melt. Stir until smooth, heating more as needed to get all the lumps out.
Add the cereal and pretzels and stir until coated well.
Allow mixture to cool slightly before adding the chocolate.
Sprinkle half the chocolate over the marshmallow-cereal mixture, mix quickly so it doesn’t melt everywhere, and then dump into the pan. Sprinkle the rest of the chocolate on top and press down into the pan.
Sprinkle with some flaky salt, cool, cut and serve.