Cabbage and Plantains with Pigeon Peas and Buttermilk

Criteria for a Tamilian kootu are not too many: one, two, or as many vegetables as you want to get rid of from the refrigerator; pigeon peas, split green lentils, or yellow split peas as the protein; a coconut- or spice-based sauce; and a tadka (whole or ground spices sizzled in hot oil), usually of black mustard seeds and fresh curry leaves. I have included four kootus in this section, two wi