In a large pan, add olive oil, and sliced mushrooms. Cook for about 12 minutes on medium until all liquid is gone. Reduce heat.
Add minced onions and garlic, stirring for 2-3 minutes.
Add truffle oil.
Add cauliflower puree and stir everything for about 3-4 minutes on medium-low heat.
Add green beans, and salt and pepper to taste. Mix until all green beans are covered in puree.
Pour green bean cauliflower mixture into a casserole dish and top with crushed crackers or almond meal.
Cook for 30-35 minutes or until top is golden brown.
In the meantime, add sliced onions to a pan with about ¼ cup olive oil. Cook on medium high, stirring the onions and making them crispy. Make sure you’re stirring occasionally so they don’t burn.
Once green beans are cooked, remove from oven and top with crispy onions