How to make
First put the onions in the blender and turn on pulse mode. Take them out into a bowl and subsequently chop in the remaining vegetables (don't overdo it so they don't turn to paste).
Stir well and leave to drain in a colander. Distribute the spice into individual plastic baggies and put them in the freezer. Whenever you need some, simply break some off and add to your dish.
I store onions the same way (if they've started to spoil), peppers, parsley, dill etc.
The exact ratio of the ingredients is to your personal preference, you can add or remove any.