1. Prepare the vegetables by slicing or chopping them into bite-sized pieces. You can use a variety of vegetables such as bell peppers, cauliflower, carrots, celery, etc. Mix them together in a large bowl.
2. In a saucepan, combine the white vinegar, water, granulated sugar, minced garlic, salt, dried oregano, crushed red pepper flakes, celery seeds, and mustard seeds. Bring the mixture to a boil over medium heat, stirring occasionally to dissolve the sugar and salt.
3. Once the mixture is boiling, remove it from the heat and let it cool for a few minutes.
4. Pour the hot brine mixture over the prepared vegetables in the bowl. Make sure all the vegetables are submerged in the brine.
5. Let the mixture cool to room temperature, then cover the bowl with plastic wrap or a lid.
6. Refrigerate the giardiniera for at least 24 hours before serving to allow the flavors to develop.
7. Serve the hot Italian giardiniera as a condiment or antipasto alongside sandwiches, salads, or charcuterie boards. Enjoy!

This tangy and spicy giardiniera will add a burst of flavor to any dish! Adjust the amount of crushed red pepper flakes to suit your preference for heat.