The Third Piece of the Puzzle

I know it's all about The Third Plate these days, but I have another dilemma in my house, namely the Third Piece issue. That is, in the meat-veg-starch triumvirate, I usually have the meat and vegetable down, but lately I've been stumped by what else goes on the plate that my brown-rice and bean-hating kids will be excited about, but that isn't a big p…