?Spicy onion paste is a condiment made from onions, chili peppers, and other spices. It is commonly used in Indian cuisine, but can be used in other dishes as well.

Cut the onions in very thin slices but do not chop them
Heat extra virgin olive oil and butter in a pan, add the onion slices and coarsely ground black pepper and let simmer at very low heat for 45 minutes, while occasionally stirring.
Add balsamic vinegar and continue the simmering for another 5-10 minutes.
Let the paste cool overnight in the refrigerator.
The paste can best be served as a condiment to, e.g. plaice or paté.
Ingredients
Directions
Cut the onions in very thin slices but do not chop them
Heat extra virgin olive oil and butter in a pan, add the onion slices and coarsely ground black pepper and let simmer at very low heat for 45 minutes, while occasionally stirring.
Add balsamic vinegar and continue the simmering for another 5-10 minutes.
Let the paste cool overnight in the refrigerator.
The paste can best be served as a condiment to, e.g. plaice or paté.