Marshmallow treats can skew saccharine, but this slightly more sophisticated version embraces the salty as much as it does the sugary. Sweet marshmallows and chocolate are balanced by plenty of salt: in the butter, on the pretzels and in the flaky sea salt finish. Butter-flavored pretzels (“butter snaps”) have a delicate crunch and a creamy note that work well in this recipe, but any small, thin pretzels are also good. You'll want to use chopped chocolate here instead of chips: They melt…
