About a year-and-a-half ago, we posted a recipe for crispy diner-style fries along with fry sauce, a species that seems to be indigenous to Utah/Southern Idaho. Being a born-and-bred Utah girl, of course I love my fry sauce. But this is the next step up–something you don’t have to apologize for or explain to people who may not be familiar with the pink stuff. This is full-blown grown-up fry sauce. And I can’t think of anything savory that it wouldn’t be good on.

Ingredient Notes
- The Basics – Ketchup, mayonnaise, fresh garlic, red onion, and fresh lime juice are things you probably already have on hand. Fresh garlic and lime juice really do make a difference!
- Creole Mustard – Don’t worry, you can find Creole mustard at most major American grocery stores (Zatarain’s is widely accessible and inexpensive). It is really uniquely flavorful and so good; if you’re looking for a great ground mustard, this is one of the best options. Walmart also makes a surprisingly good stone ground mustard.
- Capers – If you are wondering (or ever have, or will now that I’m bringing it up) what capers are, they’re little buds from the caper bush, which grows in the Mediterranean. The buds are plucked off the bush before they can bloom and then they are pickled. They’re salty and mild and add a similar flavor to dill pickles, only a little more subtle and complex (hence the grown-up dipping sauce). If you can’t find capers, dill pickles would do in a pinch.
- Cayenne Pepper – A little bit adds a kick of flavor without too much spice. If you’re worried about heat, start with a little less than a quarter teaspoon of cayenne pepper and then, after you’ve mixed everything together, add a little more until the sauce is as spicy as you’d like it.
Instructions


- Combine all the ingredients (some ketchup, mayo, capers, minced garlic, red onion, fresh lime juice, mustard, cayenne pepper, and salt) in your blender or in the small bowl of your food processor (if you have one) and blend until the desired consistency is reached.

- After you’ve mixed your sauce, store it in the refrigerator for at least an hour and up to a week. Serve it on whatever you want and prepare yourself for a little subtle finger-licking…

Serving Suggestions
In addition to the diner-style fries, you could try it on:
- Oven Steak Fries
- Sweet Potato Fries (the honey-lime dip is awesome, but just in case you feel the urge to mix it up)
- Crispy Coconut Chicken Fingers
- Crispy Shoestring Onions
- Spread it on buns of Smash Burgers
- Use it as a sandwich spread, especially hot turkey, roast beef, or corned beef sandwiches
- Omit the ketchup and use lemon juice instead of lime juice for a crab cake remoulade
Frequently Asked Questions
- Can I make this ahead of time? Yep. This dipping sauce is best when it’s had a chance to chill and allow the flavors to blend. Mix it up when you’d like and use it up within 7 days.
Did You Make This?
I’d love to hear from you! Snap a picture and tag me on Instagram, then come back and give this recipe a rating!

Grown-Up Dipping Sauce
Ingredients
- 1/4 cup mayonnaise1/4 cup ketchup1 1/2 tablespoon capers drained and minced1 1/2 teaspoons minced garlic1 1/2 teaspoons finely minced red onion1 teaspoon fresh lime juice2 teaspoons creole or dijon mustard1/4 teaspoon cayenne pepper1/8 teaspoon kosher salt
Instructions
- Combine ingredients in blender or the small bowl of a food processor. Blend until smooth. Refrigerate for at least 1 hour before serving.








Questions & Reviews
Filled with stuff I would never seek out to eat, yet still looks like it might be worth a try…how odd is that, lol. Here in OK…if fries are dipped at all, they are dipped in ketchup, ranch or gravy, lol.
Love this! Reminds me of Bel Frites in California… fries with new spices and sauces totally trump the traditional ketchup these days. Very creative
This sounds so yummy! Can't wait to try it- I bet it would be awesome one burger.
Brian and Anne–You pose a tricky question. 🙂 Honestly, once you get all the flavors in there, the capers really don't taste very caper-y. They do add a little zip, though. So if you really, really don't want to add them, you might need to add a little dill pickle juice or dill pickle relish (although not the full 1 1/2 tablespoons–maybe closer to 2 teaspoons of dill relish).
Carlie–The great thing about Creole mustard is that it's not super mustard-y to start with; it's not as spicy as brown or traditional ground mustard and it's not mustard-y at all like yellow mustard. I accidentally left it out of this particular batch at first and I knew something was off and then as soon as I added it, it really rounded out the flavors. There are so many strong flavors going on here (garlic, onion, capers, ketchup, cayenne) that the mustard is actually one of the mildest elements. Hope that helps! 🙂
♥ frozen fries ♥
♥ mustard ♥
Gotta try it!!
Question – Our family does not like mustard at all. SO I wondering if this sauce has mustardy taste at all? We love fry sauce in this house, so the idea of this grown-up sauce sounds yummy but I'm worried about the mustard.
Can I forgo the capers? I really dislike the flavor… to say the least… or would that change the integrity of the dish entirely?
Alyssa–Hahaha, those are totally the frozen Checkers fries from the grocery store! I was going to make my own, but these shorter days (and less natural light) + picking up my kindergartener from school keep throwing me for a loop!
Looks YUMMY!! I want to know the recipe for the fries in the photo too! They look delicious. Are those the diner-style fries from your blog?
This sauce looks and sounds amazing! I've been looking for a sauce to go with quesadillas and I think this will be great! Thanks for the awesome recipe.