Start by making the cauliflower rice. Place the florets in the bowl of a food processor and pulse a few times until they become small granules. (Don’t overdo it, people. You don’t want cauliflower mush.) Heat 1 tablespoon of the oil in a large skillet over medium heat. When hot, add the cauliflower rice and cook for 3-4 minutes just until tender. Season with salt and pepper to taste. Cover and set aside.
In a small bowl, whisk the chicken or vegetable stock, soy sauce, cornstarch, mirin, and honey (if using). Set aside.
In your largest pan, heat the remaining 2 tablespoons of oil over medium-high heat. When hot, add the bok choy stalks and shiitakes, spreading into a single layer. (It will seem like a LOT of bok choy and mushrooms, but they’ll cook down.) Cook without moving until the vegetables are starting to brown on the bottom, 2 to 3 minutes. Stir and cook for 2-3 minutes more until softened slightly.
Add the garlic, ginger, crushed red pepper, and the bok choy leaves and stir to combine. Cook until fragrant, about 1 minute.
Pat the shrimp dry and season on both sides with salt and a pepper. Add the shrimp to the vegetables and cook until just pink, about 2-3 minutes.
Push all the ingredients to the outer edges of the pan. Pour the stock mixture into the center, and simmer until thickened, about 2 minutes. Stir everything together to combine and coat, then remove the pan from the heat. Taste the stir-fry and add salt and pepper as needed.
Serve the stir-fry over cauliflower rice. (You may need to quickly re-heat the cauliflower rice before serving.)