Turn on oven to 450 degrees. There are a few methods to start the bread. Chop the cauliflower tops and add to a food processor to get the consistency of rice. Both options of cauliflower (pre-riced, frozen or chopped) will need to be steamed or sauteed in a pan. After cauliflower is cooked, remove the excess water by squeezing out the cauliflower in a cheese cloth (alternatively use a dish cloth) until it's completely wrung out. You want to make sure it is dry so that the bread easily forms.
Place cauliflower in a bowl with egg, 1/2 cup cheese, 1/2 cup almond flour or 2 tbsp coconut flour and spices and mix well. Place parchment paper down on a cookie sheet (I like to use when baking) and mold the bread into four slices. Bake until the bread gets crispy (18 minutes).
Turn oven up to broil or instead fry the grilled cheese on a cast iron pan. If you are going with the baking route, remove the crust from the parchment paper and place directly on cookie sheet. Now you can assemble the sandwiches by placing the cheese on top a slice of "bread" and add your favorite toppings such as: pesto, tomato, slice of turkey, bacon, avocado, salami, onions, olives......endless possibilities!
Note: with most of my recipes I don't follow them exactly! Every time is different (even with chocolate chip cookies!) So, these are all "suggestions." The reason I cook this way is because I've found it so much fun to experiment and try out various methods. And also, if there is an ingredient I'm missing, it doesn't get me completely stuck. For example, if you don't have any eggs, try making a substitute out of ground flax with a 1:1 ratio of water & flax. Or mix up the cheese blend by comping sharp white and pepperjack. Maybe combine fresh herbs like Basil and incorporate it in the sandwich with a slice of an heirloom tomato.