Quarter the head of cabbage, remove the core, and pulse the quarters in a food processor until the pieces are rice-sized. Set the cabbage rice aside.
Heat 2 Tbsp avocado oil in a large skillet over medium-high heat. Add the diced onion and the chopped apple and cook, stirring occasionally, until the onion begins to turn translucent, about 5 minutes.
Add the chopped mushrooms and the minced garlic to the skillet and cook, stirring occasionally, until the mushrooms begin to soften, about 3 minutes.
Push the vegetables to one side of the skillet. Add the ground turkey to the empty side, let it brown without stirring for 1–2 minutes, then flip/break and brown for another 1–2 minutes. Break the turkey into pieces and stir it together with the vegetables.
Add the chopped zucchini, 2 tsp dried oregano, 1 tsp ground ginger, and 1 tsp sea salt (or to taste). Stir to combine, cover the skillet, and cook about 5 minutes, or until the turkey is cooked through and the zucchini has softened.
Uncover, add the 4 cups baby spinach, and stir until the spinach is wilted, about 1–2 minutes. Taste and adjust seasoning if needed.
While the turkey mixture is cooking (or after), heat the remaining 2 Tbsp avocado oil in a second large skillet or wok over medium-high heat. Add the prepared cabbage rice and sprinkle with 1/2 tsp sea salt (or to taste). Cover and cook, stirring frequently, until the cabbage softens and begins to turn golden-brown, about 8 minutes.
Divide the cabbage rice among bowls and top with the ground turkey and vegetable mixture. Serve immediately.