Penne alla Vodka

Method

1. sweat7 min
   butter, medium-low, no colour on the onion
   butter (+ olive oil) + onion until soft, then + garlic (+ chilli flakes) for a further minute. Garlic last and briefly — it has a fraction of the onion's water and burns in the time the onion needs
2. caramelize5 min
   tomato paste smeared across the pan, medium, stirred constantly
   + tomato paste, cooked until it darkens from bright red to brick and starts to stick and smell sweet rather than tinny. This is the step most versions rush: raw paste is sharp and metallic, and five minutes of direct contact with hot fat browns its sugars and amino acids into something much deeper. Keep it moving; it scorches quickly once dry
3. deglaze3 min
   vodka in, scraped, until the pan is nearly dry
   + vodka, which lifts the browned paste off the pan and then cooks away. Give it long enough that no raw spirit smell remains — ethanol boils at 78°C, so this is quick, but leaving it short is the one way this ingredient makes the dish worse instead of better
4. boil9 min
   well salted, to 2 minutes short of the packet, water reserved
   pasta, keeping two cups of the water. Undercooked on purpose — the last two minutes happen in the sauce, where the pasta absorbs tomato and cream instead of water
5. reduce4 min
   cream in, low, half a cup of pasta water
   + cream + pasta water, simmered gently until it coats a spoon. Add the cream after the vodka has gone: dairy dropped into a hot acidic pan can curdle, and the alcohol makes that likelier
6. emulsify4 min
   drained pasta into the sauce, tossed hard, cheese off the heat
   pasta + sauce, tossed over medium heat until it clings, then + parmesan off the heat. The starch in the pasta water is what binds the fat from the cream and butter into a single glossy sauce rather than a pink liquid with grease at the edges. Loosen with more pasta water as needed and serve at once (+ basil)