1. Mix water, vinegar, salt, and sugar in a small pot and bring it to a boil.

2. Meanwhile, peel and slice the onions into thin rings. If you have a mandoline, now's the time to use it. Add the onions to the boiling liquid, turn off the heat, and let them sit for about 10 minutes to cool down. Then strain them.

3. Use the waiting time to bake the baguette rolls in the oven according to the package instructions. Let them cool slightly.

4. Heat sunflower oil in a pan and fry the sausages on medium heat, turning until evenly browned.

5. Wash and dry the lettuce leaves, then cut them into broad strips.

6. Slice the baguette rolls open and generously spread each half with flavorful remoulade.

7. Place the crispy lettuce on the bottom halves of the rolls.

8. Top with the sausages and drained onions. Close the rolls and your grilled sausage sandwiches are ready to enjoy. Tip: The sweet-sour onions can be kept in the fridge tightly covered for about a week and are perfect for cheese and sausage breads or many meat dishes.