Preheat the oven to 450 degrees F. Set out a large 18X13 inch rimmed baking sheet.
Set out a food processor. Cut the stalks off the broccoli. Cut them into rough chunks. Place the stalks in the food processor and pulse until the pieces are as small as rice. Dump the broccoli rice onto the baking sheet.
Cut the broccoli tops into large florets. Place them in the food processor and pulse until the florets are as small as rice. Dump the broccoli rice onto the baking sheet. *If you have a very large high-powered food processor, you do not need to separate the stalks from the tops.
Drizzle olive oil and garlic salt over the broccoli rice. Toss the rice with your hands, to coat. Then spread it out in a thin layer across the baking sheet.
Roast for 5 minutes. Use a large flat spatula to flip the rice and re-spread in a thin layer. Then roast another 5 minutes. Serve warm.