Using a flat or box grater, grate the onion and add to a medium-sized mixing bowl.
Measure and add to the bowl the sunflower oil, ketchup, red wine vinegar, sugar, Worcestershire sauce, and paprika.
Using a whisk, blend all the ingredients. For the first minute or two, it will seem like the oil does not want to blend with the other ingredients. Keep whisking; the sauce will come together. Season to taste with kosher salt and pepper. I add just a pinch of both.
Transfer the sauce to a squeeze bottle and refrigerate at least 2 hours before serving.
Store in the fridge for up to 10 days.
Enjoy Everything Sauce on salad, fries, eggs, tacos, rice and beans, sandwiches, and just about everything else.