In a microwavable steamer, or in a steamer basket on top of the stove, steam the asparagus, onions, and sliced potatoes until they are almost soft.
In a medium bowl, beat the eggs and add the salt and pepper.
In a large ten-inch skillet, heat the canola oil over medium heat.
Add the steamed asparagus, onions, and potatoes and sauté them in the oil for just one minute.
Pour the eggs over the asparagus and potatoes.
Let that cook in the pan, pushing the eggs with a spatula to the edge of the pan so the liquid eggs go to the rim and underneath; cook until most of the eggs on top are cooked.
Get a dinner plate and place it upside down on top of the frittata.
Tip the skillet quickly upside down so the frittata moves onto the plate.
Slide the frittata back into the skillet so the uncooked side goes back in the bottom of the skillet.
Let that side of the frittata cook for just a minute or two more.
Slide the frittata onto a serving plate.