In a large skillet, combine 2 tablespoons of butter and 1 tablespoon of olive oil over medium-high heat. Allow the butter to melt until it becomes fragrant and bubbly—about 1 minute. Then, add 1 diced onion, stirring for about 3 minutes until softened.

Incorporate 8 ounces of sliced mushrooms into the skillet. Cook them for 4 to 5 minutes, stirring occasionally, until they release their moisture and begin to brown.

Introduce 4 cups of cauliflower florets to the skillet. Stir and sauté for about 8 to 10 minutes, watching as the cauliflower turns golden and crispy around the edges.

Pour in ½ cup of vegetable stock, allowing it to combine with the skillet's ingredients. Let this mixture cook for an additional 2 minutes.

Mix in 1 teaspoon of dried thyme, 1 tablespoon of fresh parsley, and 3 minced garlic cloves. Sauté for 30 seconds until the garlic is fragrant.

Season the skillet with salt and pepper to taste and sprinkle the remaining parsley over the top before serving.