This is something I've been making for years. It's one of the easiest dishes to throw together and also one of the fastest. Depending on the pasta's cooking time and the amount of peppers and onions you want to use this will take you between 15 and 30 minutes to prepare. How's that for simple?
You can use any color pepper or onion - whatever you have on hand is good. I usually like to really up the color with red, yellow and orange peppers but today I only had one red pepper in the fridge and it needed to be used before it kicked the dust.
I'm also really partial to red onions in this dish because the color *oomph* is so awesome.
So all you need is some onion, some pepper, some garlic (because where there are onions there should always be garlic), a nice olive oil and fresh basil. Sometimes the basil is wildly overpriced, or you just can't find it any where. This dish is just fine without it - but if you can get your hands on some it really is a perfect little sparkle of flavor here.
Just put the pasta on to boil and then chop everything else up. Don't go nuts with a small dice, bigger is better here. Even the garlic is best when sliced in large pieces (it gets really sweet and you'll be happy for a big yummy bite of it!) Saute the onions and garlic in some olive oil in a pot with high enough sides that you can add the pasta. When the onions and garlic start getting translucent throw in the peppers.
By the time the pasta is done your sauteed veggies should be soft and tender, but not mushy! Drain the pasta and toss it into the veggie pot and stir it up. You can add a bit more olive oil if you need to - everything should have a slight sheen of olive oil. Not dripping oil, of course, but just a light coating.
The last step is to toss the fresh, chopped basil in and mix it together. Season with a bit of real sea salt and that's it. Now eat!
You can also omit the pasta, throw in some chopped veggie sausage and serve it on a roll. You'll feel like you're at the San Gennaro festival! Not that San Gennaro has Vegan versions of the Sausage and Pepper hero, but, oh you know what I mean!