Pasta doesn’t need to be precooked. If yours wasn’t cooked in the allotted time then there could be a few reasons for it: were you using regular pasta or whole wheat? did you follow the instructions to the T or made some adjustments? are you at regular altitude or high altitude? was the seal on your IP set correctly or was it loose? And finally, people have different tastes and some prefer softer pasta. I have been making pasta in my IP for a few years and 5 minutes is always plenty.

I think you could follow the recipe the same way. I assume that meatballs are frozen and cooked, right? I wouldn’t change anything in the recipe if that is the case. Perhaps no need to saute since they are frozen. Timing should stay the same most likely as it’ll just take longer for IP to come to pressure but other than that it shouldn’t change.

I’d use 1-2 teaspoons of tomato pasta and maybe extra 1/4 cup liquid. I’m afraid that adding more liquid may make the sauce too liquidy.

Do you have fresh tomatoes? If so, I’d add diced fresh tomatoes instead. If no fresh, then you could use 1-2 teaspoons of tomato pasta and you might want to add a bit more broth/liquid as tomatoes have that. Not sure how much though. As for cream cheese, it adds the creaminess. If you don’t have enough, don’t worry about it. It should still turn out fine. You might want to add a splash of cream after everything is cooked. Since you don’t have diced tomatoes and I’m not sure about the amount of liquid you’d need to add, you most likely will end up with a few pieces of spaghetti/fettucine stuck together on top and a bit firmer than you’d like. This is fine and expected. Just mix everything really well and push the pasta under the sauce, they’ll get unstuck in a few minutes. I’ve made this recipe with double the meatballs once which meant that the pasta was piled higher than the liquid, so the top layer was stuck together but after mixing everything and letting it sit in the sauce for a few minutes, all the pasta got separated and softened.

I just saw that the cream cheese was a half cup, not a cup, so I should be fine with that. But still wondering about the paste. Thank you!!

Your favourite seasoning mix. You can do some dried herbs, garlic powder, lemon zest, onion powder etc