Rinse and dry the produce. Add the quinoa, 1¼ cups water, and a pinch of salt to a small saucepan. Bring to a boil over high heat, reduce heat to a simmer, cover, and cook quinoa until water is absorbed and spirals start to burst, about 12 to 15 minutes. Thinly slice the red cabbage. Peel the onion and thinly slice just half. Peel and chop the apple.
Set your oven to broil on high. Trim the leaves and stem from the cauliflower– leave the whole head intact if possible. Slice the cauliflower into 2 inch thick steaks, keeping the florets intact. Gently coat the steaks in 1 tbsp olive oil, salt, and pepper on a baking sheet. Place on the middle rack and cook until golden brown in places, about 16 to 18 minutes.
Place a large skillet over medium-high heat with 1 tbsp vegetable oil. Once hot, add the sliced onion and apple and cook until softened, about 2 to 4 minutes. Add red wine vinegar, agave, ¼ cup water and bring to a boil. Stir in the cabbage, reduce heat to low, and cover. Cook cabbage until softened, about 8 to 10 minutes. Finely chop the parsley leaves and remaining onion. Mince the garlic.
Once the cabbage is finished, transfer to a bowl and cover to keep warm. Return the skillet to medium heat with 1 tsp vegetable oil. Add 1 tbsp chopped onion and garlic and cook until fragrant and softened, about 2 minutes. Stir in the dijon mustard, vegetable broth powder, and ⅓ cup water and bring sauce to a simmer. Simmer the sauce until it’s reduced by half, then remove from heat.
Remove the sauce from the heat and stir the vegan butter, vegan creamer and half of the chopped parsley into the sauce and season with salt and pepper.
Season the cabbage with salt. Divide the quinoa and braised cabbage between large plates. Top with cauliflower steaks and dijon sauce. Sprinkle with remaining parsley.