Heat a large skillet over medium-high heat and add a tablespoon of olive oil. Once shimmering, add sliced mushrooms and cook until golden and fragrant, about 5 minutes. Remove and set aside.
In the same pan, add a little more oil if needed and toss in minced garlic. Cook for about 30 seconds until fragrant, stirring constantly to prevent burning.
Pour in the Marsala wine, scraping up any browned bits from the bottom of the pan. Bring to a gentle simmer and cook until reduced by half, about 5-7 minutes, until syrupy and fragrant.
Add chicken broth and stir to combine, then return the cooked mushrooms to the pan. Let simmer for another 2 minutes to meld flavors.
Season the shrimp with a pinch of salt and add them to the pan in a single layer. Cook for 2-3 minutes per side until they turn pink and are just cooked through, with a slight curl.
Add the butter to the skillet and swirl until melted, coating the shrimp and sauce to create a glossy finish.
Sprinkle chopped parsley over the dish and squeeze fresh lemon juice for brightness. Toss gently to coat everything evenly.
Let the dish rest for a minute, then serve immediately, garnished with extra parsley and lemon wedges if desired.
