Taco Bell's Breakfast Quesalupa. Source: author.

Like any good early adopter, I decided to stop by my local Taco Bell this morning to see if the Quesalupa could be a game changer for parent company Yum! Brands (YUM -0.88%).

I was too early. My Taco Bell doesn't start serving the regular menu until 9am. However, hanging next to the signs promoting the Quesalupa that was advertised during the Super Bowl -- the cheese-stuffed Chalupa flatbread shell housing a ground beef taco -- was another sign promoting the breakfast varieties of the new offering.

The Quesalupa shell gets filled with scrambled eggs, potatoes, shreds of cheddar, and either bacon or sausage for Taco Bell's breakfast Quesalupa.

It's been two years since Yum! Brands decided to give Taco Bell a morning edge by offering proprietary breakfast items. The signature item at the time was the Waffle Taco with scrambled eggs, cheese, and a meat protein served in a folder waffle as a taco shell. Last year the waffle was replaced with a more malleable biscuit shell. Now consumers are quietly discovering today that they can get their breakfast tacos served in cheesy Chalupa shells.

Having now sampled all three -- as my taste buds duke it out with my arteries -- the breakfast Quesalupa is my favorite. The crispy yet doughy consistency of the fried flatbread bridges the gap between the waffle and folded biscuit perfectly.

Despite Taco Bell throwing marketing muscle behind the Waffle Taco, A.M. CrunchWrap, and Biscuit Taco over the past two years, the quiet launch this morning of what could be the best thing on the Taco Bell breakfast menu could be a game changer.

I had to review the Super Bowl ad again, making sure that it didn't totally ignore this morning's breakfast debut.

There's no mention of the breakfast Quesalupa, and even those that preordered what was then the $2.99 mystery item sight unseen last week only had the option of getting the ground beef Quesalupa on Saturday afternoon.    

This is a stealth attack on McDonald's (MD -0.68%). Taco Bell was already rolling. The chain's 4% year-over-year uptick in comps for Yum! Brands in its latest quarter was better than the showing at sister concepts KFC and Pizza Hut. However, anecdotally speaking, I've never seen morning commuters lining up at Taco Bell the way that they do at McDonald's. When it comes to fast-food chains, McDonald's owns the breakfast daypart, mostly because other burger flippers have simply tried to copy Mickey D's signature sandwiches. That is certainly not what's happening at Taco Bell. It's trying to stand out with items that you can only get at the Yum! Brands quick-service chain.

It was testing a croissant breakfast taco late last year at some of its stores, but that probably won't be necessary if the breakfast Quesalupa -- ultimately Taco Bell's best-kept secret this weekend -- does the trick.