How do I stop all the sauce from being absorbed and the pasta going soggy?

The secrets to a good pasta bake are:

• Pick the right pasta: unless you are making Lasagna, tube shaped pasta is the best choice because it holds sauce, and tends to be thicker. Thicker pasta is better than thin in a bake, because thin pasta will get soggy way too easily. Penne works fine, so does macaroni. I think rigatoni is best, because it has ridges on the outside which help hold sauce on.
• Undercook the pasta: if you cook the pasta until it's done and then bake it with a sauce, it will keep right on cooking and get mushy. What you want do to is cook the pasta until it starts to soften, but isn't quite edible yet. A minute before you reach al dente would be how I describe it. This way it cooks perfectly as it bakes.
• Right amount of liquid in the sauce: the ideal result is to have a bake that holds together well without being dry. The pasta will absorb water as it cooks, so you need enough liquid to allow it to rehydrate, but not so much the dish comes out runny. Once it's all mixed and in the baking dish, check to make sure there's some liquid on the bottom. You want enough loose liquid to cover the bottom. If there isn't enough add some of the pasta water or stock - slowly, don't overdo it - then bake it covered for the first 15-20 minutes. If there's too much liquid in the bottom, bake it uncovered so more evaporates.

As for what type of sauce to use and what to put on the top, it really depends on taste. Some people use a tomato sauce, others a white sauce (mac and cheese is a white sauce with cheese in it), some people use both, typically layered. You can do a meat sauce or vegetarian - chunky or smooth, there's too many possibilities to list and it's opinion based on what is best. You need to consider the audience and what their dietary needs/preferences are and choose a combination that satisfies as many as possible.

I'd recommend the following for pasta bakes / casseroles:

1. Use a relatively thick pasta, not strands. Tubes like ziti, penne, rigatoni are good, as are spirals like rotini. When cooking, you should start checking it a minute or two before the package instructions say, and pull it when it's no longer crunchy but not necessarily fully cooked.

2. Cook the pasta, then dress it in a little bit of sauce so it doesn't stick too much, then let it cool down. You can then add more sauce to it when you prepare the casserole dish. Once the pasta's cool, it won't absorb as much liquid, so it's less likely to suck up all of the moisture.

Even if it does soak up the moisture, it's generally not a big deal for a casserole -- I've made some that are more 'slicable' than 'scoopable' and no one complained.

I personally stick with tomato sauce for this sort of thing (vs. a dairy based sauce) as I find it easier to reheat -- just put it in a moderate (300 to 350°F / 150 to 175°C) until it's warmed through ... or mostly warmed through (tomato sauce is more forgiving if it's not fully warmed through).

If you've topped it with a melting cheese (vs. a grating cheese), you can cook it covered until the cheese starts to melt, then uncover and place it under the broiler for a minute or two 'til the top browns.

If you're not sure if you're going to be able to warm things back up, I either go with pesto or a vinaigrette based pasta salad / pasta primavera, as you can serve them cold.

Twenty people is enough that I'd consider making at least two casseroles; one large casserole in your largest container means that it's going to take longer to heat up. (it's a function of how deep it is in the container)

And as long as you're making two, I'd ask people about dietary restrictions -- you might want to make one meat and/or dairy free.

I used to cook spaghetti for 80 football players.

I made the pasta in batches al-dente - meaning you don't boil the regular spaghetti noodles past 13 minute. If you use a roaster, you can dry reheat the pasta by putting water between the outside heat source and roasting pan. This will allow the pasta to reheat without moisture. Stir it every 10-12 minutes for about 1 hour before serving.

Make the sauce and store in a large crock pot or roster. DO NOT store sauce and pasta before serving. If it's an alfredo you can combine 10-20 minutes before serving. Lemon butter sauce the same. Red sauce - just let people put what they want on top.

I suggest

• Cooking the pasta a little under al dente
• Avoiding delicate pastas, like angel hair
• Carrying the sauce separately and
• Mixing the pasta and sauce together prior to re-heating.

The first is meant to cause the pasta to be perfectly done on re-heating. The second will reduce the probability of broken pasta in your final dish. The third and fourth to avoid soggy pasta at the end.

When I make pasta for myself, I typically buy a four-serving package of frozen ravioli and a four-serving jar of bolognese sauce, and dump the entire package of ravioli into a pot of boiling water (no salt), wait for it to be cooked, then strain out all the water and put it back into the pot before emptying out the sauce jar and cooking it some more while stirring continuously to prevent sticking until I can hear the sauce bubbling.

I then turn the flame off, and serve up a quarter of it to eat that night, and ladle the rest into an airtight container that I stick in the fridge. Then, each night for the next three nights, I take out the container, serve up a portion into a microwave-safe bowl, and then microwave it for 60 seconds. If you want a creamier sauce, you can add in a table-spoon of Greek yoghurt after it's been heated up and served into a bowl, and then mix it in with the sauce.

Is it the best ravioli in the world? Probably not, but it's edible, easy, relatively cheap, and I like it. I'm not sure how well this process would scale up to a 20-serving meal, though.