Sweet and sour Brussels sprouts

• 600g Brussels sprouts
• 1 onion, minced
• 1 celery stalk, minced
• ½ tbsp sugar
• 2 tbsp balsamic vinegar
• 1 tbsp capers
• 40g butter
• Rosemary
• Salt
• Pepper

1. Clean the Brussels sprouts thoroughly and cut the bigger ones in half. Cook over steam for about 5 minutes. Remove from heat and set aside.
2. Melt butter in a pan over low heat. Add the onion, celery, rosemary and a pinch of salt. Toss in the Brussels sprouts and cook for a few minutes. Then, sprinkle over the sugar. Stir well and pour in the balsamic vinegar and a ladle of boiling water, and continue cooking for 5 minutes.
3. Before taking off the heat, toss in the capers and let flavours absorb. Adjust seasoning before serving.