Pound the chicken thin using a rolling pin or cut horizontally in half to about ½ inch thickness and season with salt and pepper.
Melt 1 tablespoon butter or olive oil in a large pan over medium-high heat, and add chicken and sear on both sides for 4-5 minutes on each side. Remove the chicken from the pan and set aside.
Reduce the heat and add the remaining 1 tablespoon butter to the same pan. Add garlic and saute for 30 seconds or until garlic begins to brown; Add sundried tomatoes, spinach, heavy cream, parmesan cheese, and mix through.
Return chicken to the pan and simmer for another minute and remove from heat. Serve immediately with pasta, zucchini noodles, steamed vegetables, salad, or rice.