Cook the chicken: Pat the chicken dry with paper towels and season all over with ½ teaspoon salt, pepper, and oregano. Heat 2 tablespoons of olive oil in a 10-inch or larger skillet over medium-high heat until simmering. Working in batches, if needed, add the chicken and sear until deeply browned, 3 to 5 minutes per side. Transfer the chicken to a plate and set aside while you make the sauce.
Make the sauce: Reduce the heat to medium and add the remaining 1 tablespoon olive oil to the skillet. Add the shallot and sauté until softened and lightly browned, about 1 minute. Add the sun-dried tomatoes, garlic, and remaining ¼ teaspoon salt, and sauté until fragrant, about 30 seconds. Add the white wine and scrape up any browned bits from the bottom of the skillet with a wooden spoon. Simmer until the wine has reduced by about half, 30 seconds to 1 minute. Stir in the heavy cream and Parmesan. Add the spinach a handful at a time, stirring after each addition until all the leaves are wilted into the sauce, 2 to 3 minutes.
Add the chicken and serve: Return the chicken and any juices on the plate to the skillet. Simmer until the chicken is warmed through and the sauce is slightly reduced and thickened, 3 to 4 minutes. Serve. Love the recipe? Leave us stars and a comment below!
