Begin by heating the olive oil and butter over a medium-high heat in a large saucepan. As the buttered oil starts to sizzle, add the diced onions and sea salt. (Adding the salt now means the onions will soften more quickly and draw more of their flavor into the oil and butter.) Turn the heat to low-medium, and cook slowly for about ten minutes with some frequent stirring. The onions shouldn’t brown at all.
Add the chilies and garlic. Turn the heat to medium high, stirring for about 90 seconds to pull out the flavor of both.
Add all the cherry tomatoes, return the heat to medium-low and cook for 10 minutes until the tomatoes start to lose some of their body – help them on their way with some stirring and crushing.
Once this is starting to look like a sauce, add the canned tomatoes and the sugar – which will cut the tomatoes slightly sharp acidity. Continue cooking and for another ten minutes. You’re aiming to reduce it down to the thickness of a good tomato ketchup, but to also keep a little body in the tomatoes. This isn’t a completely smooth sauce. Turn off the heat, put a lid on the pan, and let it sit while you cook the pasta.
Cooking the pasta
Fill a good-sized saucepan ¾ full of water, add the salt and bring the water to the boil on high heat. Now add the pasta and keep the heat on high until the water returns to the boil. Turn down the heat to medium-low and let the pasta cook for 10 minutes at a fairly brisk, bubbling simmer.
Try a piece of the penne – it should be just (and I mean just) – al dente. If it isn’t, let it keep bubbling and wait for a few more minutes – until it is al dente. Drain the pasta. I use a big colander for this and give it a good shake to remove all the cooking water.
Bringing it all together
Start by heating the sauce on medium heat until it just starts to bubble. Now add all the pasta, cut the heat back to low and gently stir the pasta so it all becomes coated in sauce. Serve at once in large bowls with a fork and spoon.
Notes
On the choice of peppers: That bright red is seriously important. You don't only want to taste them in this dish, you want to see them. On heat - personal tolerances rule the roost here. Remember, this is supposed to be a powerfully hot dish – proceed accordingly. Red jalapeños work, but I used red serrano peppers here. Parmesan cheese sprinkled heartily over the top? For me, always. No question.And a pairing - olive ciabatta. Even though it might sound like a carb-overload, chunky, buttered slices of this crusty loaf go with it really well. Great for rounding-up the last of the sauce in your bowl.To drink, I’d choose a dry, sparkling white wine or a good, crisp Italian beer – maybe a Peroni or a Moretti.