Start by patting the chicken breast dry with paper towels, ensuring it's moisture-free for a perfect sear. Season both sides thoroughly with salt, black pepper, and half the dried oregano.

Heat 2 tablespoons of olive oil in a large skillet over medium-high heat. Add the seasoned chicken and sear for about 5-6 minutes until golden brown and cooked through, then set aside.

Add 1 tablespoon of olive oil to the skillet and sauté the minced garlic for about 30 seconds until fragrant. Add the diced red bell pepper and sliced yellow squash, cooking for 4-5 minutes.

Stir in the halved cherry tomatoes and cook for a further 2 minutes. Add the cooked chicken back into the mix.

Return the seared chicken to the skillet, add fresh spinach, the remaining oregano, and red pepper flakes, and cook for 2-3 minutes until spinach wilts.

Remove from heat and grate fresh lemon zest over the dish, stirring gently. Adjust seasoning with more salt and pepper if needed.