Preheat oven to 190 °C (375 °F).

In a non-stick skillet set over high heat, heat half the oil and butter. Sauté mushrooms for 3–5 minutes or until browned. Add shallot and spinach. Season with salt and pepper. Cook for 1 minute. Remove from heat. Set aside on a plate.

In the same skillet, add remaining oil and butter. Cook pork slices for 2 minutes on each side.

Finish cooking in the oven for 10 minutes.

Remove from oven. Top each piece of meat with mushroom and spinach mixture and cheese slices.

Bake for a few minutes until cheese starts to melt slightly.

Remove from oven. Serve immediately with mashed potatoes.