Cut 8 of the scapes in half lengthwise and set aside. With a fine grater, grate the remaining scapes and set aside.
In a large pot of salted boiling water, cook the pasta until al dente. Add the 16 garlic scape halves 2 minutes before the end of the cooking time. Reserve 1/2 cup (125 ml) of the cooking water. Drain the pasta and scapes.
In a large skillet over medium heat, cook the grated garlic scapes and red pepper flakes in the oil for 1 minute. Remove from the heat. Add the drained pasta and scapes, cheese, lemon zest and reserved cooking water. Mix well to evenly distribute the flavours. Season with salt and pepper.
Divide the spaghetti among four plates. Drizzle with olive oil and sprinkle with more cheese, if desired.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.