Preheat oven to 400F or 375F(convection oven). In a food processor, process cauliflower, carrots, and broccoli to a little larger than rice grain size.
Line a large sheet pan (you might need twwith parchment, season with salt, pepper, ginger, garlic, onion and toss with olive oil. Spread the “rice” in a single layer. Bake for 20 minutes. Remove the sheet from oven, fluff the rice, then bake an additional 15 minutes. Set aside to let cool. It’ll crisp further.
In the meantime, prepare garlic, onion, and scallions. Butterfly the shrimp. Chop broccoli stems to smaller rounds and dice the leafy part to slightly larger pieces. Combine the oyster sauce, fish sauce, and white pepper in a bowl.
Pre-heat a large saute pan or wok over medium heat until it’s too hot to place your palm nearby, about 2-3 inches away. Turn the heat up to medium-high, add 1.5 tbsp avocado oil, fry the shrimp with garlic for about 2-3 minutes without touching then flip to cook 1 minute additional. Set them aside along with the pan juices.
Use the same pan, add 1.5 tbsp oil. Saute onion and white scallion parts, and season with a pinch of salt over medium-high heat until fragrant, about 10 seconds. Add broccoli stems and season with another pinch of salt. Saute until the stems turn softer, about 10-15 seconds. Add the broccoli leafy parts, keep sautéing until they turn deeper green color. Add the sauce and shrimp back to the pan, give a quick toss. Off heat, season with a small pinch of white pepper.
In a large serving tray, layer the shrimp and vegetable saute in the bottom layer. Toss in cauliflower rice. Garnish with green scallion parts and serve with lime wedges on the side.
If baking the rice with 2 sheet pans, the tray in the lower rack will get baked quicker than the middle rack. Keep an eye on it. A slight burnt bits are totally normal and part of the charm. :)
You can swap shrimp for ground chicken, pork, or beef. Season the meat with 2 pinches of salt during saute. Taste and adjust with more stir-fry sauce.