How to make it
Bring a large saucepan of salted water to a boil. Heat a frying pan until it starts to smoke and add the onions. Fry onions without any oil, tossing frequently for 2-3 minutes.
Start adding the olive oil and toss for about a minute until all onion is lightly coated with the oil. Add 'nudja to the pan and lightly crushed with a wooden spoon until the fat has rendered out.
Add tomatoes and XO Sauce and toss together. Remove from heat. Plunge the fresh tagliatelle in boiling salted water.
Allow to cook for 1 minute, stirring constantly. Remove pasta from water and toss with ragu. Finish with fresh chives and a squeeze of fresh lemon.