Preheat the oven to 450 degrees F.
Remove the outer leaves from the cauliflower, and cut it into florets. Place them in the bowl of a food processor (Don’t have a food processor? See notes for option*), and pulse until the cauliflower is finely chopped. It should look like rice.
Transfer the cauliflower to a microwave-safe dish or bowl. Cover and cook in the microwave for 10 minutes or until very soft. (Depending on microwave, cooking time may vary so check and little early and add time if needed.) Alternatively, you can steam the cauliflower in a steamer basket on the stovetop until very soft.
When the cauliflower is cool enough to handle, transfer it to a bowl lined with a clean tea towel. Bring the ends of the towel together and squeeze as much liquid out of the cauliflower as you can. There will be a good bit. Set aside.
In a mixing bowl, whisk the egg, and then mix in the Italian seasoning, salt, pepper, and the other ½ cup of cheese. Add the cauliflower, and stir to thoroughly incorporate. I find it easiest to use a dinner fork to break up the cauliflower that has been squeezed into a ball. (*Prep-ahead tip:* At this point, you can place the mixture in an airtight container or covered bowl and refrigerate until ready to bake.)
Transfer the mixture to a baking sheet lined with parchment paper. Form the dough into a rectangle about 8 x 12 inches and ¼-inch thick.
Bake for 15-20 minutes** or until golden brown and crisp around the edges. Remove the baking sheet from the oven, and sprinkle the remaining ½ cup cheese over the top. Bake another 5 minutes until cheese is melted.
Cut into 16 breadsticks. Serve plain or with marinara sauce for dipping.