Onion Caramelization – Does Caramelizing an Onion Increase Its Non-Dietary Fiber Carbohydrates?

You can add a handful of pumpkin seeds or sunflower seeds. You don't need to adjust any of the other ingredients.

Sunflower seeds contain a ton of good stuff, including fibre, according to Wikipedia:

"In addition to linoleic acid (an essential fatty acid), sunflower seeds are also an excellent source of dietary fiber, some amino acids (especially tryptophan), Vitamin E, B Vitamins (especially vitamin B1 or thiamine, vitamin B5 or pantothenic acid and folate), and minerals such as copper, manganese, potassium, magnesium, iron, phosphorus, selenium, calcium and zinc.[5] Additionally, they are rich in cholesterol-lowering phytosterols."

You know, I have always liked to eat spinach with vinegar. Just steamed and with a splash of plain white vinegar. It is a very common way to eat spinach around here.

Anyway, I suppose it could have some affect on iron absorption. Large amounts of vitamin C can increase non-heme iron absorption by as much as 200%. This article, http://pubs.acs.org/doi/abs/10.1021/jf0203040, seems to indicate that acetic acid, the main component in vinegar, may also increase iron absorption.