Cook the spaghetti in salted boiling water until tender, 7 to 9 minutes. Drain and reserve.
In a large sauté pan, heat the oil over medium heat. Add the leek and garlic and saut´ until tender, about 2 to 3 minutes.
Add the peas and pasta, and toss to combine. Continue to toss until the mixture is heated through. Season with red pepper flakes, salt, and pepper. Using a spatula or tongs, push all the pasta to one end of the pan.
Crack an egg into the empty side of the pan. Season it with salt and pepper, and reduce heat to low. Cook the egg until your desired doneness. Transfer the pasta to a large bowl and finish with parmesan cheese. Top with the egg and serve.
I always carry three kinds of hot sauce in my purse. I have a soft spot for making people their favorite dessert, especially if it's pie. My first cookbook, The Fearless Baker, is out on October 24, 2017.