The grilled cheese wars have been raging online for years.
Both sides were convinced they had the superior method.
And Tillamook's new two-word product just settled one debate that sent GenZ into meltdown.
The butter-versus-mayo debate has dominated TikTok food discussions since 2020.
Home cooks posted side-by-side comparisons testing which spread creates the perfect golden crust on grilled cheese sandwiches.
The butter camp argued their method delivers richer flavor and that traditional browning you get from dairy fat.
Mayo defenders countered that their technique produces more even browning thanks to mayonnaise's higher smoke point.
Both sides accumulated hundreds of thousands of views arguing their case.
Now Oregon-based dairy giant Tillamook just ended the fight with a product nobody saw coming.
Tillamook teams with Japanese mayo legend to drop Butternaise
Tillamook partnered with cult-favorite Japanese brand Kewpie to create Butternaise – a first-of-its-kind spread combining butter and mayonnaise specifically engineered for grilled cheese.¹
The spread blends Tillamook Extra Creamy Unsalted Butter with newly released Kewpie Organic Mayonnaise plus zesty spices.²
Tillamook Executive Chef Josh Archibald said the combination delivers what neither condiment can achieve alone.
"By combining both butter and mayonnaise, you get the best of both worlds," Archibald explained. "Butter brings the savory, luscious richness while mayonnaise brings crisp, light, almost croutonesque vibes to the sandwich."³
The formula took two years to perfect.
Archibald has been using this butter-mayo blend as his secret weapon at Tillamook's Oregon creamery food hall, where the double cheddar grilled cheese sells hundreds of thousands of units annually.⁴
Now home cooks can access that exact recipe.
Butternaise launches November 6 exclusively at shop.tillamook.com as part of a $15 grilled cheese kit.⁵
The kit includes an 8-ounce jar of Butternaise, two packs of Tillamook cheddar cheese slices, and a spreader.
Why Kewpie mayo brings something American brands can't match
Kewpie isn't some trendy ingredient Tillamook grabbed because it's popular on social media.
The Japanese brand has dominated Japan's mayonnaise market since launching in 1925 and appears in virtually every Japanese household.⁶
What separates Kewpie from Hellmann's or Duke's comes down to fundamental differences in how it's made.
American mayo uses whole eggs. Kewpie uses only egg yolks – giving it a richer, more custardy texture with that distinctive yellow color.⁷
Each bottle contains about four egg yolks worth of richness.
The brand also uses rice vinegar instead of white vinegar, creating a gentler acidity and subtle fruitiness American brands don't deliver.⁸
But here's what really matters for grilled cheese: umami.
The Japanese version contains MSG – monosodium glutamate – which delivers that savory depth professional chefs obsess over.⁹
Kewpie's American version swaps MSG for yeast extract to avoid the controversy around MSG that still lingers despite scientists proving it's safe.¹⁰
That umami component is what makes Butternaise more than just mixing butter and mayo at home.
The seasoning blend adds garlic, onion, and paprika notes that kick the flavor up another level while the butter provides browning and the mayo ensures even heat distribution.¹¹
The data shows America picked butter – but they were missing half the answer
Tillamook surveyed grilled cheese makers before developing Butternaise.
The results? An overwhelming 71% of people spread butter on the outside of their bread while only 12% go for mayo.¹²
Those numbers explain why the TikTok debate generated so much heat.
The butter majority felt vindicated by tradition while the mayo minority insisted their method produced superior results.
Both camps had valid points.
Butter delivers that rich dairy flavor Americans associate with classic comfort food.
Mayo's higher smoke point prevents burning and creates more consistent browning across the entire bread surface.
Mixing them isn't exactly revolutionary – professional chefs have been doing versions of this for years.
What makes Butternaise different is that it comes pre-blended with proper ratios and seasoning so home cooks don't have to experiment.
The limited-edition nature also creates urgency – Tillamook announced supplies are limited and won't last long after the November 6 launch.¹³
That scarcity combined with solving a genuine cooking debate positions this for viral success.
Dean Paradise, Executive Creative Director at Leo Chicago, explained the strategic thinking behind launching on National Sandwich Day.
"The butter versus mayo debate has been raging online for years," Paradise said. "Rather than pick a side, we found a way to give people the best of both worlds while showcasing Tillamook's innovation in the dairy space."¹⁴
Jinny Lam, VP Marketing at Tillamook, added context about why they're finally sharing their secret weapon.
"Our chef's Butternaise recipe has been our secret weapon for years – it creates that perfect golden crust that makes all the difference," Lam stated.¹⁵
The launch follows Grilled Cheese Fest that Tillamook hosted in Los Angeles bringing together chefs and food creators to celebrate America's favorite comfort sandwich.
Now the question shifts from butter versus mayo to how fast Butternaise sells out when it drops.
¹ Tillamook County Creamery Association, "A New Condiment Has Entered the Chat: Meet Butternaise," PR Newswire, November 3, 2025.
² Ibid.
³ The Kitchn, "This First-of-its-Kind Spread Makes the Best Grilled Cheese of Your Life," November 3, 2025.
⁴ Ibid.
⁵ Tillamook Shop, "Tillamook Butternaise," accessed November 6, 2025.
⁶ Mashed, "The Untold Truth Of Kewpie Mayonnaise," April 15, 2020.
⁷ Chowhound, "How American Kewpie Mayo Differs From The Original," August 25, 2024.
⁸ Parade, "Everything You Need to Know About Fan-Favorite Kewpie Mayo," May 4, 2025.
⁹ Chowhound, "What Is Kewpie Mayo And Why Do Chefs Say It's The Best?," July 6, 2024.
¹⁰ Ibid.
¹¹ AOL, "Should You Use Butter or Mayo on Your Grilled Cheese? Tillamook Just Solved the Debate," November 3, 2025.
¹² The Kitchn, "This First-of-its-Kind Spread Makes the Best Grilled Cheese of Your Life," November 3, 2025.
¹³ Taste of Home, "Tillamook's New Butternaise Promises the Perfect Grilled Cheese," November 3, 2025.
¹⁴ Marketing Communication News, "Tillamook Settles the Great Grilled Cheese Debate," November 3, 2025.
¹⁵ Ibid.