Alu Palak
You’ll often see the word saag (shaak in Bengali) used as a synonym for spinach in the US. In fact, saag/shaak refers to any kind of leafy greens. Thus spinach (palak in hindi, palok-shaak in Bengali) is only one kind of saag/shaak and various other kinds of leafy greens (from mustard greens to beet greens to amaranth leaves to water spinach) are eaten as saag/shaak. As far as I know Swiss chard is not grown much (or at all) in India, but unsurprisingly it is very good when used in most saag/shaak recipes (though I wouldn’t use it in recipes that call for leafy greens to be steamed and pureed).
Traditionally, Bengali meals incorporate one shaak dish, and this recipe is for the simplest possible such preparation plus an easy variation. It will go excellently with yesterday’s mushoor dal for a simple vegetarian meal. You could make it with spinach, radish greens, beet greens etc. (or some combination)—I used chard here because it’s what I had at hand.