Prepare the jars. Wash the jars with hot, soapy water, then place them in a water bath canner filled with water and keep them hot. Wash the lids and rings with hot, soapy water and set aside.
Make the spice bag. Place 3 bay leaves and the whole black peppercorns into a spice bag or cheesecloth tied securely with kitchen string.
Make the brine. In a large stockpot, combine the white vinegar, water, granulated sugar, pickling salt, and spice bag. Bring to a boil over medium heat, then cover, reduce the heat, and simmer for 5 minutes.
Cook the vegetables. Add the cauliflower, onion, celery, carrots, and zucchini to the pot and bring to a boil. Reduce the heat, simmer for 5 more minutes, then remove from heat.
Add the peppers. Remove and discard the spice bag, then stir in the chopped red bell pepper and serrano peppers.
Season the jars. Remove the hot jars from the canner. Add one bay leaf, one garlic clove, ½ teaspoon celery seed, and ½ teaspoon fennel seed to each pint jar.
Fill the jars. Pack the vegetables into the prepared jars with a ladle, leaving ½ inch headspace. Ladle the hot brine over the vegetables, maintaining the same ½ inch headspace.
Remove air bubbles. Run a bubble remover or chopstick around each jar to release trapped air. Add additional brine if needed to maintain proper headspace.
Add the pickle crisp. Add ¼ teaspoon to each jar, if using.
Seal the jars. Wipe the jar rims with a clean damp cloth, then apply the lids and rings until fingertip tight.
Process the jars. Place the jars in the canner with at least one inch of water covering them. Bring the water back to a full boil and process for 10 minutes, adjusting for your altitude if necessary.
Rest in the canner. Turn off the heat, remove the canner lid, and let the jars sit for 5 minutes.
Cool the jars. Remove the jars to a heat-safe surface and let cool undisturbed for 12-24 hours.
Check the seals. Confirm each lid has sealed before storing.