Preheat the oven to 350°F (176°C).
Prep the ingredients per the instructions above.
Season the chicken on both sides with salt, pepper, and oregano. Heat the oil in a skillet over medium heat. Sear until golden brown on both sides. Transfer the pan to the oven and cook to an internal temperature of 160°F (71°C) using a thermometer. Set the chicken on a cutting board.
In the same skillet over medium heat, melt butter. Stir in garlic and cook until fragrant, about 1 minute. Add in tomatoes and season with salt and pepper. Cook until tomatoes are beginning to burst then add spinach and cook until spinach is beginning to wilt.
Stir in heavy cream and parmesan and bring the mixture to a simmer. Reduce heat to low and simmer until sauce is slightly reduced and creamy, about 3 to 5 minutes. Return chicken to skillet.
Warm the bread in the oven for about 2 minutes. Spread with butter if desired.
Serve the chicken with bread and sparkling water.