Taco Bell will begin officially testing a new waffle taco on Thursday in about 100 units in three markets, along with a number of other potential additions and tweaks to its still-in-progress breakfast menu.

The new test breakfast menu will be introduced on Aug. 8 in units throughout the Fresno, Calif.; Omaha, Neb.; and Chattanooga, Tenn. markets.

In addition to the waffle taco, other new menu items in the test include oatmeal with fresh berries; a fruit-topped yogurt-and-granola parfait; and the MTN Dew Kickstart fountain drink, a new product by PepsiCo that blends Mountain Dew and orange juice.

Taco Bell’s new test menu is an effort to improve on breakfast offerings currently in about 850 Taco Bell locations, mostly in the West. The chain is working toward a systemwide rollout of the morning daypart by next year, hoping to capture a piece of the estimated $42 billion American diners spend on breakfast in restaurants, according to a 2011 report by research firm Technomic.

Liz Matthews, Taco Bell’s chief food innovation officer, said the company sees the addition of the breakfast as “a journey” that will take time to get right before being introduced throughout the 6,000-unit system. Breakfast — or “First Meal,” in Taco Bell parlance — will likely play a key role in the Irvine, Calif.-based chain’s ability to achieve its goal of doubling sales from $7 billion to $14 billion over the next decade, she said.

“We’ve been really happy with the performance [of breakfast] so far,” said Matthews, though the company declined to give specifics on sales. “As we go into this test we’re being really open because we’re learning. We’re going to get this right.”

The hot item in this test version is expected to be the waffle taco, which the company micro-tested in five Southern California restaurants earlier this year to work out operational aspects. An Instagram post by a customer who stumbled across the waffle taco went viral, sparking about 4 million impressions, according to company estimates.

The product is just what it sounds like, said Matthews: a waffle shaped like a taco, with a crispy outside and fluffy inside. The waffle cradles scrambled eggs and a sausage patty and is served with a packet of syrup for a recommended $1.79.

Consumers have also indicated they want more options, so the test menu will also include the yogurt parfait, featuring vanilla Dannon yogurt topped with a strawberry-blueberry fruit blend and granola for a recommended $1.99.

Another more-healthful alternative is the oatmeal, featuring rolled Quaker oats, which is also topped with the fresh strawberry-blueberry blend, for a recommended $1.99.

The test will also include items that are already on the breakfast menu that have proven popular. Among them is the A.M. Crunchwrap, which Matthews said has been a real “driver” of the morning daypart.

Similar to the popular Crunchwrap Supreme of later dayparts, the A.M. Crunchwrap features scrambled eggs, bacon or Johnsonville sausage, crispy hash browns and melted cheese stuffed inside a flour tortilla and grilled, for a suggested $2.49.

“Customers have always loved the Crunchwrap, and this version is entirely portable, with all of your breakfast on the inside,” said Matthews. “This is one of our most popular items on the menu.”

Also unchanged are the Cinnabon Delights, warm doughnut holes filled with Cinnabon frosting and covered with cinnamon sugar. The sweets sell for a suggested two for $1; four for $1.49; or a 12-pack for $4.49. Because the Cinnabon Delights have been so popular, the chain is planning on offering them all day, not just at breakfast, in the 850 units where they are available, Matthews said.