Onions peel and in fine cubes cut. Clean the chilli, cut lengthwise, wash and remove the seeds. Cut the pod into fine strips. Heat oil in a pan, sauté onions in it, add sugar, let caramelize. Deglaze with vinegar. Add chilli.
Simmer on low heat until the liquid thickens slightly. Season with salt and pepper. Pour into previously rinsed glasses. Close the glasses tightly, leave them on the lid for about 5 minutes, turn them over and let them cool down. Tastes good with hard cheese