Whataburger sells bottles of their spicy ketchup in grocery stores for about $4 to $5 for 20 ounces. A cup of Heinz ketchup costs roughly $0.40, and the spices needed to convert it add about $0.15 worth of pantry staples. That puts your homemade batch at around $0.55 for the same amount — an 85% savings.

Beyond cost, making it yourself means you can dial in the heat level. The store-bought version has a fixed spice profile, but your version can be mild for kids or nuclear for the friend who puts hot sauce on ice cream.

The original gets its character from a specific balance of heat and earthiness. Cayenne provides the upfront burn, but it’s the cumin and smoked paprika that give it depth. Without those two spices, you’d just have spicy tomato sauce. With them, you get a condiment that tastes layered — sweet from the ketchup base, sharp from the vinegar, warm from the cayenne, and slightly smoky from the paprika.

Whataburger’s version also has a smoother heat curve than just dumping hot sauce into ketchup. The cayenne pepper distributes evenly through the thick ketchup base, so the heat builds gradually with each bite instead of hitting you all at once on the front of your tongue. This makes it more versatile because the heat enhances food rather than overpowering it.

The vinegar and Worcestershire sauce serve a critical purpose. They sharpen the overall flavor and prevent the ketchup from tasting flat or one-dimensional. Ketchup is already sweet and acidic, but these additions punch up the tang just enough to keep your taste buds engaged. It’s a small touch that separates a good copycat from a great one.

• Let it rest overnight. Thirty minutes is the minimum, but the flavors integrate fully after 8 to 12 hours in the refrigerator. If you can make it the night before you need it, do that.

• Adjust the heat in small increments. Start with 1 teaspoon of cayenne if you’re sensitive to spice, then add 1/4 teaspoon at a time until you reach your preferred level. You can always add more but you can’t take it out.

• Use smoked cayenne if you can find it. It adds another layer of smokiness that brings the recipe even closer to the original.

• Try it as a marinade. Thin the spicy ketchup with a little olive oil and use it as a glaze for grilled chicken thighs or pork chops. The sugars in the ketchup caramelize on the grill and create a sticky, spicy bark.

• Make a spicy fry sauce. Mix equal parts of this spicy ketchup with mayonnaise for a creamy dipping sauce that works on burgers, fried fish, and sweet potato fries.

Spicy ketchup stores in the refrigerator for up to 3 weeks in a sealed jar or squeeze bottle. The flavor actually improves over the first few days as the spices fully hydrate and blend into the ketchup base. You may notice the heat intensifies slightly after a day or two — this is normal.

No reheating is needed since this is a cold condiment. If the ketchup separates slightly after sitting in the fridge (a thin layer of liquid on top), just give the jar a good shake or stir before using. For the best texture, pull it from the refrigerator 5 minutes before serving so it’s cool but not ice-cold, which allows the flavors to come through more clearly.