Heat the olive oil in a large skillet over medium heat, then add the salt-and-pepper-seasoned chicken. Cook the tenders for 5 to 6 minutes per side, until they are golden, then transfer them to a plate.

Melt the butter in the same skillet and cook the shallot, stirring frequently. Continue until the shallot softens and turns translucent without browning heavily.

Add the mushrooms, season with salt and pepper, and cook them with the sage. Sauté for about 5 minutes, until the mushrooms are golden brown and smell deeply savory.

Pour in the dry marsala wine and scrape the skillet bottom as it bubbles. Let the wine reduce by about half, leaving a lively sizzle and concentrated browned bits in the pan.

Stir in the chicken broth and heavy whipping cream, then bring the sauce to a boil. Cook until the sauce begins to thicken and leaves a smooth coating on the back of a spoon.

Return the chicken and any juices from the plate to the skillet. Cook for another 3 to 5 minutes, until the chicken is heated through and coated in the sauce.