Follow these straightforward steps to create your pickled onions, peppers, and carrots:

1. Prepare Your Vegetables: Thinly slice the onions, bell peppers, and carrots. Use a mandoline for uniformity if available.
2. Make the Brine: In a small saucepan, combine vinegar, water, sugar, and salt. Heat the mixture over medium heat until the sugar and salt dissolve. You do not need to boil it.
3. Add Optional Ingredients: If you’re using mustard seeds, black peppercorns, or garlic cloves, add them to the brine and stir well.
4. Pack the Vegetables: In clean jars, layer your sliced vegetables, making sure to pack them tightly.
5. Pour the Brine: Carefully pour the hot brine over the vegetables in the jars. Ensure that the vegetables are fully submerged.
6. Seal the Jars: Allow the jars to cool slightly before sealing them with lids.
7. Refrigerate: Place the sealed jars in the refrigerator. The pickles will be ready to eat after at least one hour but are best if allowed to pickle for a day or more.
8. Enjoy: Start enjoying your pickled onions, peppers, and carrots with your favorite dishes!

These steps make it easy to have delicious pickled vegetables ready for any occasion.