Combine all of these cooking ideas (the one I would have mentioned is mise en place but GG beat me to it), while making a simple recipe.
Fresh basil chiffonade (teach them what chiffonade is) and if you don't know I will tell you
Canned whole tomatoes
salt and pepper
Fresh grated Parmesan cheese
2 kalamata olives per person
In this case the mise en place is pretty easy. Just chop the garlic and put in a small bowl, drain and then crush the tomatoes with your fingers reserving this juice and the tomatoes in a bowl. Cut the basil chiffonade and put in a bowl, grate the cheese, etc., etc. Explain that you know for SURE you can make the recipe because by doing this you know for CERTAIN you have all the ingredients. While the garlic is heating (in a skillet, not pot) you don't have to chop the tomatoes; possibly burning your garlic while doing so.
If you choose to chop the garlic you can very roughly chop the garlic and then show them how to place one hand on top of the knife, while holding the blade, and rock the blade so it chops the garlic or you can show them how to use a garlic press.
Once the garlic has warmed in the oil a bit you can add the tomatoes You can show the benefit of a skillet because the larger base of the skillet will help reduce the liquid out of the sauce faster.
Heat the olive oil on low, add the garlic but don't allow any color to come to it. Add the drained, squished tomatoes and cook until a lot of the liquid has reduced. This won't take that long in a skillet...maybe 15 - 20 minutes on medium heat. At some point near the end toss in the kalamata olives and heat a bit more. When done remove from heat and toss in the basil chiffonade. While the basil is heating in the pan you can talk about the pasta. Always cook pasta in a VERY large pot so the starches release and don't cause the pasta to become clumped and stuck together. The most important time to stir pasta is shortly after putting into the water You also want to salt the water because this is when it will flavor the pasta. All aspects of a dish need to be flavored. The same goes for cooking potatoes for something line potato salad (even mashed potatoes). Potatoes need to be cooked beginning with cold water though. If the pasta is already done then the salt will just cling to the outside, but, potatoes will absorb the salt all the way through. So when you bite into potato salad the inside is seasoned as well.
...back to marinara sauce. I prefer this marinara with angel hair, but, if you use a spaghetti noodle you can actually show them how to tell if it is cooked other than by just tasting it. If you bite into a spaghetti noodle it will be a bit white in the middle - the "raw" part, if you will.
Once the pasta is cooked add to the skillet and toss with the marinara. When combined and heated show them how to plate it in an attractive way. It can either be placed right in the center and stacked kind of high or placed in an oblong oval shape. Foods placed in the center of a plate are more attractive than foods spread all the way to the sides of the plate.
I know you are probably tired of reading this by now. Sorry, I got carried away