Place chicken breasts between two layers of plastic wrap and pound with a meat mallet or rolling pin to a uniform thickness. Discard plastic and transfer chicken to a clean work surface. Cut into bite-sized pieces and set aside.

Heat olive oil and garlic in a large high-sided skillet over medium-high heat. Sauté garlic for several minutes until golden brown. Remove garlic with a slotted spatula and discard.

Add chicken to hot skillet and cook until golden brown on each side, approximately 3-4 minutes per side. Season with salt and black pepper, to taste. Remove chicken from skillet and set aside.

Add half & half and chicken broth and scrape up any brown bits from the bottom of the pan with a spatula. Add oregano and grated cheese to skillet and whisk until cheese is completely melted, approximately 3-4 minutes.

Reduce heat to just below medium and add the sun-dried tomatoes and baby spinach. Simmer for 3-4 minutes, stirring occasionally, or until tomatoes are softened and the spinach wilts.