Domino's (DPZ) is going right to the heart of Pizza Hut's business with this week's launch of pan pizzas.

Domino's is now selling the pizzas, which are thicker than its normal fare, at all of its U.S. stores, reports USA Today. Pizza Hut pretty much owns the pan pizza category, which is estimated at $6.4 billion.

But Pizza Hut, which is owned by Yum Brands (YUM), isn't raising any alarm bells. "I'm not terribly worried," its chief marketing officer tells USA Today. "We've been the world leader in pan pizza for 30 years. We're 100% confident that we have the right product."

Domino's is putting a lot of work into its new pizza. It even delivers the pizza in a snazzy black box. The Huffington Post tasted the new pie and said it tastes a little better than Pizza Hut's. "This is the kind of crust that is so overloaded with salty flavors that you can feel your heart pick up the pace after a few bites," writes the Huffington Post.

Domino's has been busy overhauling its operations this year. It's making its stores more approachable and comfortable for pickup customers. And it's dropping the "Pizza" because its stores will have a wide variety of grab-and-go items that aren't pizza at all, including pasta, salad, wings, chicken sandwiches, parmesan bread, sodas and chocolate lava cakes.

Investors must be liking the new pan pizza, because Domino's shares have risen 7% this week since the news came out. Domino's shares have been on fire in the last year, rising some 33% to trade Thursday afternoon at $37.66. Shares of Yum Brands have dropped just slightly this week and were trading Thursday at $67.56.

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