How do i avoid the bitter taste when softening red onions?
Hi Stanley & Welcome to Cheftalk :)
With the red onions, I usually find if you are finding any food bitter, a dash or two of sugar certainly helps. Just add a little, then keep tasting as you go, add more if needed.
Simply by reducing the heat to less than 1/4th of it's full capacity! Just don't let them color and you can soften them during a longer time without going bitter. Same goes for all onions and especially for garlic.