Start cooking the pasta (I have long subscribed to the less-water method Harold McGee addresses here).
Take the bacon out of the package, cold out of the refrigerator, and cut across the slices into 1/2" wide blocks. Cook in a skillet over medium heat, stirring and breaking up the blocks with a wooden spoon.
Dump the peas into a Pyrex bowl with a little water and microwave 3-4 minutes, until they are warm, stirring halfway through.
While all the cooking is going on, Mix the egg, parmesan, and pepper (to taste - it's best to use a lot, but for kids, maybe less) in a large bowl. It should have the consistency of thick batter.
When the pasta is done, drain it quickly. Don't linger, as it's good to capture some of the water. Dump the steaming spaghetti into the egg mixture, and agitate well to cook the egg. Add the bacon with a slotted spoon. Some purists will just empty the skillet into the bowl, but that is too much. Mix in the peas, and you're done. The biggest challenge is to get the bacon and peas mixed in evenly - I recommend steel tongs.