Toast the slices of bread in the oven or toaster (optional).
Add the avocado and lemon juice to a mixing bowl and mash with a fork. You can also mash the avocado onto your bread, but I prefer to use a bowl.
Divide the mashed avocado evenly among the toasts, and top with a pinch of salt, nutritional yeast (1 teaspoon per toast), garlic powder (⅛ teaspoon per toast), and a dash of red pepper flakes (optional).