Cut off the bottom quarter of the asparagus stalks. (You can use the bottoms if you like for another purpose—see Notes.) If you're working with rather thick asparagus, you'll want to peel the stalks as well. Cut the asparagus into short lengths, setting the tips apart.

In a medium-sized non-stick or seasoned carbon steel skillet, sauté the pancetta very gently in a bit of olive oil until the fat has almost completely rendered and the pancetta has (very slightly) browned. Add the spring onion and let it soften a bit.

Add the asparagus pieces, reserving the tips for the moment. Stir and sauté the asparagus for a few minutes so they absorb the flavors of the pancetta and onion. Now add enough water to almost cover the asparagus. Raise the heat and let the asparagus come to a lively simmer, adding the tips after about a minute, until all the water has evaporated and the asparagus is just slightly underdone. (If for whatever reason the asparagus is not tender enough when the water has evaporated, add another bit of water and let it evaporate.)

While the asparagus is simmering, beat the eggs in a mixing bowl with salt and pepper to taste and, if using, the grated Parmesan.

When the asparagus is done, add the beaten eggs to the skillet, folding them together with the asparagus with a spatula.

Now proceed to gently fry your frittata following the master recipe, on one side and then on the other.