Melt 2 tablespoons of the butter in a large skillet over medium heat. Add onion with a pinch of salt, and cook until softened about 3-4 minutes. Add garlic, and dry seasonings, cook until fragrant, about 30 seconds.
Add in the remaining butter, then the mushrooms, and cook, stirring often until beginning to brown, about 5 minutes. Stir in cauliflower; season with salt and pepper, to taste. Cook, stirring often, until nice and tender, about 10 minutes. Stir in lemon juice and zest, dill, parsley, and chicken stock. Simmer for an additional 3-5 minutes.
Remove from heat. Season with salt and pepper, to taste, along with fresh dill, parsley, parmesan and lemon wedges if desired. Serve these Cauliflower Mushrooms immediately.
Store in an airtight container in the fridge for up to 5 days.