Start by greasing a large pan with the butter (or bacon fat if you prefer); add your sausage (links or patties) and bacon and cook 5-10 minutes, until cooked thoroughly. Remove from the pan and keep near heat to keep warm.
Next place the sliced mushrooms in the same fat, using the leftover fat and bits to help season, cooking 5-7 minutes, stirring frequently throughout, and adding salt and pepper to desired taste.
Meanwhile, prepare your eggs as you prefer, whether that be poached, fried, soft-boiled, hard-boiled, etc.
At the same time, cook your spinach in a large pan over medium heat for 1-2 minutes, until gently wilted.
Once all your pieces are done, serve on warmed plates with your avocado slices, seasoning with salt and pepper to your desired taste.