Make the cauliflower rice: Pulse the florets in a food processor, until a rice-like texture is achieved.
Fill a large pot with about an inch of water and a vegetable steamer. Bring it to a boil.
Add the “rice” and cover. Let it steam fort 4-5 minutes until tender. Remove the steamer from the pot and let it cool.
Once the rice is cool, transfer it to a clean, thin dishtowel. Wrap up the steamed rice in the dishtowel, twist it up, then squeeze as much water as you can from the cauliflower. This is key to making a good dry crust that you can pick up with your hands. Really SQUEEZE out the water.
In a large bowl, mix the rice, beaten egg, goat cheese, and spices. Use your hands to get it very well mixed. Press the dough out onto a baking sheet lined with parchment paper. Keep the dough about ⅓” thick, and make the edges a little higher for a “crust” effect.
Bake for 35-40 minutes at 400F. The crust should be firm and golden brown.
Spread the vegan pesto over the crust. Top with sliced tomatoes and crumbled cheese. Return the pizza to the 400F oven and bake an additional 5-10 minutes, just until the cheese is hot.