Melt the butter in a skillet or large pan over moderate heat. Add the garlic and simmer for about 30 seconds or until it's fragrant and softened, about 30 seconds. Stir a few times throughout to prevent it from browning.
Add the mushrooms to the skillet, then toss them to evenly coat them in melted butter.
Slowly pour the beer over the mushrooms and bring everything to a simmer on medium-low heat.
Stir in the fresh herbs, kosher salt, and cracked black pepper.
Let the mushrooms cook for about 25-30 minutes or until all of the mushrooms have soaked up all of the liquid, stirring occasionally.