Sure, in the winter we crave ragu made with sausage and fennel, or ground beef and tomato paste; but in the summer nothing but the lightest and simplest sauce will do.
This sauce is so simple that it doesn't need a recipe. All measurements are flexible (in fact, I've never measured anything while making this sauce). If you like onions instead of garlic, then make that switch. If you like fresh oregano rather than basil, go for it. But for us, it's five ingredients, always - fresh tomatoes, garlic, basil, salt, and olive oil.
Any tomatoes will do. When I have lots of cherry tomatoes ripe on the vine, I'll use them for this sauce, halving them before roasting. Plum tomatoes and beefsteaks are of course great too. You can mix and match. Whatever you've got that's ripe, that's what you want to use. I add plenty of chopped garlic - we still have tons from our garden, though I had to transfer it to the extra fridge to keep longer. You need a handful of basil from the garden too. I like coarse sea salt here. We'll save the discussion about olive oil for another time, but you're buying the closest to local you can, right? (Imported stuff may not even be olive oil - for more info check out the book 'Extra Virginity' - you will never buy cheapo oil again.)
Preheat your oven to 375 or 400, somewhere around there. Get out a roasting pan, or a sheet pan, or a skillet that can go in the oven (actually you could do this on the stovetop too), and slick the bottom with oil. Chop up your tomatoes and garlic and spread them in the pan. Add a generous amount of salt. If you're using paste tomatoes, you'll want more olive oil; for beefsteaks, use less (because there's more juice in those). Scatter leaves of basil around. Stick the pan in the oven, and roast for at least 45 minutes (start checking around 30 minutes, especially if you're using cherry tomatoes) and up to an hour. The tomatoes should be cooked and wilted, but not blackened. Let cool in the pan, then decant into mason jars and either refrigerate or freeze.
We use this on everything - pasta, homemade pizza, bruschetta. You could use it to make a panzanella or caprese salad. You could eat it with a spoon (I certainly have). Just don't water-bath can this stuff - the inclusion of oil, garlic, and herbs makes it too low in acidity to do that safely. If you have a pressure canner, that would work.
Usually the day I make this sauce, half gets used right away, and half gets frozen for the winter. Tonight it'll be used on pizza, with Tom's homemade mozzarella. We have tried a LOT of pizza dough recipes, and have settled on this one from Alton Brown. You have to plan ahead and make it the day before, but trust me, it's worth it. (By the way, you don't need bottled water - just boil some tap water and let it sit out with the top off for a while - the chlorine will off-gas.)