In a large skillet, sauté the garlic in olive oil mixed with a knob of butter over gentle heat until it just starts to brown around the edges. Remove the garlic and discard.
Turn up the flame to medium-high and add the sliced mushrooms. Sprinkle the mushroom slices with a pinch of salt. This will cause the mushroom to exude its juices. In just a few minutes, the juices will evaporate and you will begin to hear the mushrooms start to sizzle. Continue to sauté the mushrooms, tossing from time to time, until they have lightly browned. Set aside.
Take your cutlets, cover then in parchment or wax paper, and pound them gently with a meat pounder or the back of a small skillet to flatten them a bit. Then flour them lightly.
In the same skillet where your sautéed your mushrooms, add a drizzle of olive oil and another knob of butter. Lay in your cutlets, making sure they are well spaced. (Proceed in batches in need be.) Brown them over a lively flame until they are lightly browned on both sides, perhaps a minute or two per side.
Add a good slash of white wine and let the cutlets simmer for a few minutes, turning them from time to time, until the wine has thickened into a velvety sauce.
Add back the sautéed mushrooms, along with the minced parsely if using, and mix everything together. If using the cream, add it now and let it thicken to your liking.