Pat the diced chicken breasts dry with paper towels—this is crucial for getting a golden sear. Season them generously with salt and pepper on all sides. Heat the olive oil in a large skillet over medium-high heat until it shimmers. Once hot, add the chicken and sear for 3-4 minutes per side until golden brown. Don't move it around constantly or you'll mess up that beautiful crust.

Transfer the seared chicken to a plate and set aside—you'll add it back in just a moment. In the same skillet, melt the butter over medium heat. Add the diced onion and cook for about 3-4 minutes, stirring occasionally, until it becomes soft and translucent. You'll notice the pan gets all those brown bits from the chicken—that's flavor gold right there.

Add the minced garlic to the onions and cook for just 30 seconds to 1 minute until fragrant. Be careful not to let it burn or it'll taste bitter and ruin the whole thing. Stir constantly so it toasts just right. You'll smell that incredible garlic aroma—that's when you know it's perfect.

Pour in the chicken broth, scraping up all those browned bits from the bottom of the pan with a wooden spoon. This is called deglazing, and it pulls all that trapped flavor into your sauce. Let it simmer for about 2 minutes so the broth reduces slightly. The liquid should start looking a little less watery.

Reduce heat to medium and stir in the heavy cream, sun-dried tomatoes, and fresh spinach. Don't panic if the spinach looks like way too much—it wilts down significantly. Stir everything together and let it cook for 2-3 minutes until the spinach is completely wilted and the sauce is smooth. This is when your kitchen smells absolutely amazing.

Add the grated Parmesan cheese, dried oregano, and dried thyme to the creamy tuscan chicken mixture. Stir constantly for about 1 minute until the cheese melts completely into the sauce. Taste it and adjust salt and pepper as needed—remember, you already seasoned the chicken, so go easy. The sauce should be silky and rich at this point.

Return the seared chicken breasts to the skillet and nestle them into the sauce. Simmer for about 5-8 minutes until the chicken is cooked through—the internal temperature should reach 165°F when you check with a meat thermometer. Mine usually sticks a little to the pan and that's totally fine. Stir gently a few times to coat everything in that creamy goodness.