Dunkin' Donuts has finally brought its two brands together. Image source: Baskin-Robbins.

For the past few years, fast-food chains have been in an ever-escalating battle of the outrageous.

It used to be that simply adding a new item to a menu garnered media attention and public interest. That's still true for chains with very limited selections like Shake Shack, which caused a stir by adding a chicken sandwich, but most quick-serve establishments have such bloated menu boards that simply trotting out a barbecue sauce burger no longer moves the needle.

To get attention and capture the public's fancy, a chain needs to push boundaries or combine two things that do not necessarily go together. You can partly blame Yum! Brands (YUM 0.24%) for this as its Doritos Locos Tacos set the standard for wacky pairings and some of the fault goes to baseball stadiums, which have pushed the edge of food reason by combining products that maybe should not go together.

So, in a world where snack chips can be taco shells and the Burgerizza -- a hamburger served with pizza buns -- exists, the bar has been raised. That means that a chain like Dunkin' Donuts (DNKN) can no longer capture media attention simply by adding a new flavor of doughnut or some novel beverage choices.

That makes it a little surprising that the company -- which owns both the popular doughnut chain and the Baskin-Robbins ice cream brand -- waited so long to bring its two products together.

What is Dunkin' doing?

Even though Baskin-Robbins stores and Dunkin' Donuts locations often exist side by side under the same roof, there has been very little melding of the two brands. Dunkin' has had iced coffee with flavors borrowed from the ice cream brand, but the two chains have otherwise been kept separate.

That changed on Sept. 1, when the ice cream chain began selling Donut Ice Cream Sandwiches. Customers get to pick any flavor of ice cream they want, have it topped with fudge and sandwiched in a split Powdered Donut from Dunkin' Donuts.

"With our new Donut Ice Cream Sandwiches, we've brought together two of the most delicious sweet treats from our brands, cool ice cream from Baskin-Robbins and classic Powdered Donuts from Dunkin' Donuts, into one amazing dessert," said Dunkin' Brands Executive Chef Jeff Miller. "The best part is that guests can customize their Donut Ice Cream Sandwich with any ice cream flavor, including our September Flavor of the Month, Pumpkin Cheesecake."

It's an idea so obvious you have to wonder why it took this long

Will this work?

The big challenge for Dunkin' is that the idea of an ice cream sandwich served on doughnuts no longer seems quite as outrageous as it would have just a few years ago. In a world where snack chip tacos and hamburgers served on doughnut buns have become common, the Donut Ice Cream Sandwich seems more logical than outrageous.

What Dunkin' may have working in its favor is that an ice cream sandwich with a doughnut in place of the traditional cookie wafers actually seems like a good idea. This is a bit outrageous, but it's probably closer to Shake Shack adding chicken than it is to the Miami Marlins offering a hot dog taco.

The Donut Ice Cream Sandwich may not shock people into sampling or garner much "I can't believe that exists" media coverage. But because it's a good idea, it could become a big seller for Baskin-Robbins and it has tons of sequel potential. As Taco Bell has rolled out many variations of its Doritos treat, there is no reason why Dunkin' can't add new flavors of doughnuts for its ice cream sandwich.

This may not be an instant grand slam for the ice cream chain, but it has the potential to be a slow-build hit that can be kept going with limited-time offers and special selections. Dunkin' probably waited too long to pull the trigger here, but the Donut Ice Cream Sandwich may still become a a big hit.