Preheat the oven to 400ºF. If using fresh cauliflower, fill a large pot over medium heat with an inch of water. Fit a steamer basket into the pot, then pour the raw cauliflower into the steamer basket. Bring the water to a boil and cover the pot, steaming the cauliflower until it is very tender and can be pierced with a fork.
If using frozen cauliflower, be sure to thaw it completely before getting started, then continue with the following steps.
Pour the completely thawed, or freshly steamed, cauliflower into a large food processor fitted with an "S" blade. (You may have to do this in batches if you have a smaller food processor.) Process until a rice-like texture is created. If you bought frozen riced cauliflower, you can skip this step and proceed to the next one.
Transfer the "rice" to a clean, thin dishtowel. Wrap up the steamed rice in the dishtowel, twist it up, then SQUEEZE all the excess moisture out! (Be careful if your cauliflower is still hot-- you may want to let it cool before handling.) A lot of extra liquid will be released, which will leave you with a nice and dry pizza crust.
In a large bowl, mix up the squeezed-out rice, egg, goat cheese, and spices. (Don't be afraid to use your hands! You want it very well mixed.) It won't be like any pizza dough you've ever worked with, but don't worry-- it'll hold together!
Press the dough out onto a baking sheet lined with parchment paper. (It's important that it's lined with parchment paper, or it will stick.) Keep the dough about 1/4" to 1/2" thick, and make the edges a little higher for a "crust" effect, if you like.
Bake for 30-35 minutes at 400F, until dry and golden. Use the parchment paper to flip the crust over, and bake again until the other side is nice and dry, about 10 to 15 more minutes.
Add your favorite pizza toppings to the crust, such as sauce and cheese, then return the pizza to the 400F oven. Bake an additional 5-10 minutes, just until the cheese is hot and bubbly. Slice and serve warm.
Time-Saving Tip: I recommend making a double-batch of cauliflower pizza crusts and make one for now, and save one for later. After baking the crusts, wrap up the extra pizza crust in foil, and FREEZE it for a quick "frozen pizza" to enjoy another night! All you need to do is add toppings and bake at 400F, until the cheese is hot and bubbly.