NEW YORK -- McDonald's is considering another addition to its all-day breakfast menu: Happy Meals.

The fast-food chain says it will begin testing breakfast Happy Meals in Tulsa, Oklahoma on Sept. 26. The Happy Meals come with either two McGriddles cakes or an egg and cheese McMuffin.

McDonald's Corp., based in Oak Brook, Illinois, has been trying to win back customers since CEO Steve Easterbrook took over last year. The company had conceded that it failed to keep up with changing tastes, with sales slumping in recent years.

If the test is successful and goes national, it would be the first new entree for the Happy Meal in more than 30 years, said McDonald's spokeswoman Becca Hary. The test of breakfast Happy Meals was first reported by USA Today.