This hearty bake has been feeding ranch hands and hungry families for generations. It’s the perfect blend of creamy, cheesy comfort with wholesome veggies, all baked into one satisfying dish that practically cooks itself.

This one-pan wonder is a TRUE cowboy classic, born from the need for a hearty, no-fuss meal that can feed a crowd after a long day on the range. The genius lies in the sauce: using evaporated milk creates an incredibly rich, creamy texture that won’t curdle or separate during baking like fresh cream sometimes can. For the best results, I always reach for my trusty cast-iron skillet to sear the chicken and mushrooms—it holds heat beautifully and adds a subtle, savory depth to every bite.

Ingredients

• 1.5 lbs (680g) boneless, skinless chicken breasts, cut into 1-inch cubes
• 8 oz (225g) white mushrooms, sliced
• 5 oz (140g) fresh spinach, roughly chopped
• 1 medium yellow onion, diced
• 3 cloves garlic, minced
• 1/4 cup (30g) all-purpose flour
• 1 can (12 oz / 354ml) full-fat evaporated milk
• 1 cup (225g) sharp cheddar cheese, shredded, divided
• 1/2 cup (50g) panko breadcrumbs
• 2 tbsp (28g) unsalted butter, plus more for greasing
• 1 tbsp olive oil
• 1 tsp dried thyme
• 1/2 tsp smoked paprika
• 1/2 tsp kosher salt
• 1/4 tsp black pepper
• 1 pinch red pepper flakes (optional)

Instructions

1. Preheat your oven to 375°F (190°C). Lightly butter or spray a 9×13 inch baking dish and set aside.
2. In a large cast-iron skillet or heavy-bottomed pan, heat 1 tbsp olive oil and 1 tbsp butter over medium-high heat. Add the diced onion and cook for 3-4 minutes until beginning to soften. Add the sliced mushrooms, sprinkle with a pinch of salt, and cook for 5-6 minutes, stirring occasionally, until the mushrooms have released their liquid and are golden brown. Use a slotted spoon to transfer the cooked mushrooms and onions to a bowl, leaving any residual liquid in the pan.
3. Add the remaining 1 tbsp butter to the same skillet. Season the chicken cubes with salt, pepper, and smoked paprika. Add the chicken to the hot skillet in a single layer (work in batches if needed to avoid crowding). Cook for 4-5 minutes per side, until golden brown and cooked through. Transfer the cooked chicken to the bowl with the mushrooms and onions.
4. Reduce the heat to medium. In the same skillet, sprinkle the 1/4 cup of flour over the remaining pan drippings. Whisk constantly for 1-2 minutes until the flour is lightly toasted and fragrant—do not let it burn.
5. Slowly pour in the evaporated milk while whisking continuously to prevent lumps. Bring the mixture to a gentle simmer and cook, whisking often, for 3-4 minutes until the sauce has thickened to a glossy, gravy-like consistency. Stir in the dried thyme and red pepper flakes (if using). Remove from heat.
6. To the large bowl with the chicken and vegetables, add the chopped spinach and 3/4 of the shredded cheddar cheese. Pour the warm sauce over everything and fold gently until well combined and the spinach has wilted slightly.
7. Transfer the entire mixture into your prepared baking dish, spreading it evenly. In a small bowl, mix the panko breadcrumbs with the remaining 1/4 cup of shredded cheddar. Sprinkle this mixture evenly over the top of the bake.
8. Bake, uncovered, for 25-30 minutes, or until the sauce is bubbly around the edges and the breadcrumb topping is deep golden brown and crisp.
9. Let the bake rest for 5-10 minutes before serving. This allows the sauce to set slightly for cleaner portions.