HOW TO ROAST WALNUTS: Heat a pan over medium heat and add nuts. Let them sit for half a min, or so, then stir.
Toast for about 3-4 mins, stirring constantly so they won't burn. If you don't stir, they will burn. Remove the pan from the heat and let them cool, stirring occasionally.
Chop once cool to sprinkle on top of ricotta toast.