Thoroughly wash fresh vegetables: carrots, cucumbers, bell pepper, and green beans. Cut carrots, slice cucumbers, break cauliflower into florets, and trim green beans. Peel garlic cloves.

Select clean quart-sized mason jars and fill with prepared veggies, adding garlic cloves, mustard seeds, and black peppercorns among the vegetables.

In a medium saucepan, combine equal parts water and vinegar with salt and sugar. Heat until salt and sugar dissolve over medium heat, about 5 minutes.

Carefully pour the brine over the packed vegetables in the mason jars, leaving ½ inch of headspace.

Wipe the rims of the jars and secure lids fingertip-tight. Let jars sit at room temperature until cooled, about 30-45 minutes.

Place sealed jars in the refrigerator and let marinate for at least 24 hours before enjoying.