This recipe is built on a simple framework—a creamy base, a tangy and sweet layer, and savory aromatics—and each ingredient plays a specific, important role.

1 cup mayonnaise Mayonnaise is the foundation of the dressing, providing its signature creamy, rich body. Full-fat mayonnaise gives you the best texture and flavor. If you’re looking for a lighter version, a reduced-fat mayo will work, but the dressing will be slightly thinner and less rich.

1/4 cup ketchup Ketchup gives Thousand Island its characteristic pink-orange color and contributes a combination of tomato sweetness, mild acidity, and savory depth. It’s one of the most distinctive elements of the dressing and can’t be substituted without significantly changing the character of the final product.

2 tbsp sweet pickle relish Sweet pickle relish is the ingredient that sets Thousand Island apart from other creamy dressings. It adds little bursts of tangy, sweet, slightly vinegary pickle flavor throughout the dressing and provides a subtle textural element. Don’t substitute dill relish here—the sweetness of sweet pickle relish is a defining feature of the flavor profile.

1 tbsp finely diced onion Fresh diced onion adds a mild sharpness and savory bite. Finely dicing it ensures you get the flavor evenly distributed without large pieces that overwhelm individual bites. After the dressing chills in the fridge, the onion mellows and blends beautifully into the overall flavor.

1 tsp Dijon mustard Dijon mustard adds a gentle heat and a complex, slightly tangy flavor that helps emulsify the dressing and gives it a more sophisticated character than plain yellow mustard would provide.

1 tsp white vinegar Vinegar brightens the dressing, cuts through the richness of the mayonnaise, and provides the tangy backbone that keeps things from tasting heavy or flat. A teaspoon is enough to make a noticeable difference without making the dressing too sharp.

1/2 tsp Worcestershire sauce Worcestershire sauce is a secret weapon in so many savory recipes, and it works beautifully here. It adds umami depth, a subtle smokiness, and a complexity that you can’t quite put your finger on but would definitely miss if it weren’t there.

1/2 tsp paprika Paprika adds a touch of warmth, a hint of smokiness, and contributes to the dressing’s distinctive color. Sweet paprika is the standard choice, but smoked paprika adds an interesting layer of flavor if you want to try a variation.

1/4 tsp garlic powder Garlic powder adds a savory, aromatic note that rounds out the spice profile without overwhelming the other flavors. Fresh garlic is too sharp and assertive for a delicate dressing like this—garlic powder integrates more smoothly.

1/4 tsp black pepper Black pepper adds a gentle heat and a subtle bite that keeps the dressing from tasting one-dimensional.

Salt to taste Salt brings all the flavors together and elevates every other ingredient in the bowl. Add it gradually and taste as you go, since the mayo, ketchup, and Worcestershire sauce already contribute some saltiness.