Instructions

• Preheat the oven to 350°F (180°C). Grease a 9×13-inch (23×33 cm) casserole dish with cooking spray.
• Pat the cubed chicken dry and season evenly with the kosher salt and ground black pepper.
• In a large skillet over medium-high heat, heat the olive oil and add the butter. When the butter has melted and is foaming, add the seasoned chicken in an even layer.
• Cook the chicken, stirring occasionally, until the pieces are cooked through and no longer pink in the center. Remove the chicken to a plate and set aside.
• In the same skillet over medium heat, add the diced onion and cook, stirring occasionally, until the onion is translucent, about 4–6 minutes. Add the minced garlic and cook for 30 seconds to 1 minute more until fragrant.
• Sprinkle the all-purpose flour over the cooked onion and garlic and cook, stirring, for 1 minute to remove the raw flour taste.
• Slowly pour in the whole milk while whisking or stirring to combine. Gradually add the chicken stock or broth while continuing to whisk or stir until the mixture is smooth and has thickened to a sauce consistency similar to heavy cream.
• Stir in the dried thyme, then add the frozen mixed vegetables. Return the cooked chicken to the skillet and stir until everything is evenly combined and heated through.
• Transfer the chicken-and-vegetable mixture to the prepared 9×13-inch casserole dish and spread it into an even layer. Arrange the frozen tater tots in a single layer over the top of the mixture.
• Bake uncovered in the preheated oven for 30–40 minutes, or until the tater tots are cooked through and crisp to your liking.
• Remove the casserole from the oven, sprinkle the shredded cheddar cheese evenly over the tater tots, and place under the broiler for a few minutes until the cheese is melted and bubbly (watch closely to prevent burning).
• Remove from the oven and let the casserole rest for about 15 minutes before serving. Garnish with the chopped fresh parsley.