Poblano Chicken Spaghetti Bake

Poblano Chicken Spaghetti Bake takes cozy chicken spaghetti in a fresher, slightly bolder direction. Tender chicken and spaghetti get folded into a homemade sharp-cheddar sauce with sautéed poblano peppers, red bell pepper, garlic, and fire-roasted tomatoes. Smoked paprika adds warmth without making the casserole aggressively spicy.

The sauce starts with a simple butter-and-flour base, so there is no condensed soup needed. A little cream cheese keeps everything smooth, while freshly shredded cheddar melts into the sauce and creates those golden patches across the top.

Cooking the spaghetti just shy of al dente is important because it finishes in the oven without becoming soft. Once baked, the center stays creamy while a few pasta edges turn lightly golden. Finish with scallions and cilantro for a fresh contrast to all that cozy, cheesy goodness.

Recipe Yield: 6 servings

INGREDIENTS

12 oz spaghetti
1 1/4 lbs boneless skinless chicken breasts, cut into 1-inch pieces
2 medium poblano peppers, seeded and diced
2 cups freshly shredded sharp cheddar cheese, divided
1 medium red bell pepper, diced
1 small yellow onion, finely diced
3 garlic cloves, finely minced
1 cup well-drained fire-roasted diced tomatoes
2 cups whole milk
1 1/4 cups low-sodium chicken broth
2 oz cream cheese, softened
2 tbsp olive oil, divided
1 1/2 tsp kosher salt, divided
1/2 tsp black pepper
1 tsp smoked paprika, divided
1/4 tsp ground cumin
3 tbsp unsalted butter
3 tbsp all-purpose flour
1 tsp Dijon mustard
2 green onions, thinly sliced
2 tbsp chopped fresh cilantro

INSTRUCTIONS

1. Prepare the oven:
Preheat the oven to 375°F. Lightly grease a 9×13-inch baking dish.

2. Cook the spaghetti:
Boil the spaghetti in salted water for 2 minutes less than the package directions. Reserve 1 cup pasta water, then drain.

3. Brown the chicken:
Meanwhile, season the chicken with 3/4 tsp salt, black pepper, and 1/2 tsp smoked paprika. Heat 1 tbsp olive oil in a large deep skillet over medium-high heat. Cook for 4–5 minutes, stirring occasionally, until lightly golden and nearly cooked through. Transfer to a plate.

4. Cook the vegetables:
Add the remaining 1 tbsp olive oil to the skillet. Add the poblanos, red bell pepper, and onion. Cook for 6–7 minutes, stirring occasionally, until tender with lightly browned edges. Add the garlic and cook for 30 seconds.

5. Build the sauce:
Add the butter to the vegetables. Once melted, sprinkle in the flour, remaining 1/2 tsp smoked paprika, cumin, and remaining 3/4 tsp salt. Cook for 1 minute, stirring constantly.

6. Make it creamy:
Gradually whisk in the milk and chicken broth. Simmer for 3–4 minutes, stirring frequently, until lightly thickened. Reduce the heat to low and stir in the cream cheese and Dijon until smooth. Remove from the heat, then stir in 1 1/4 cups cheddar until melted and creamy.

7. Combine the casserole:
Fold in the drained tomatoes, chicken, and spaghetti until evenly coated. If the sauce feels too thick to coat the pasta easily, add reserved pasta water a few tablespoons at a time.

8. Assemble the bake:
Transfer the mixture to the prepared baking dish and spread evenly. Sprinkle the remaining 3/4 cup cheddar over the top.

9. Bake until bubbly:
Bake uncovered for 18–22 minutes, until the sauce is bubbling around the edges, the cheese has lightly golden spots, and the chicken reaches 165°F.

10. Finish and serve:
Let the casserole rest for 5 minutes. Finish with sliced green onions and cilantro, then serve warm.

Helpful Tips to Perfect This Recipe

• Undercook the spaghetti: The pasta continues cooking in the creamy sauce during baking. Starting slightly firm keeps the final chicken spaghetti tender instead of soft.
• Brown the poblanos a little: Letting the peppers develop a few browned edges before making the sauce adds another layer of smoky flavor.
• Shred the cheddar fresh: Freshly shredded cheese melts more smoothly into the homemade sauce and gives the casserole a creamier finish.
• Keep the sauce slightly loose: Spaghetti absorbs sauce quickly. Before baking, the mixture should look a little creamier than you ultimately want it to be.