Keftes de Espinaca -- this is the closest thing I have found to Croquetas de Espinaca (Spinach Croquettes). A friend brought them over about 6 months ago and have been looking for them ever since. She bought them from a bakery that moved out of town. Even spinach haters can't resist them, especially when they're splashed with a little fresh lemon juice; fresh juice does make a major difference in taste. Onions add a sweet flavor and textural complexity.