1) Coarsely slice the mushrooms. Finely dice the garlic and onion.
2) Warm the olive oil in a large saucepan, and add onion, garlic, and mushrooms. Stir well to coat the mushrooms. Saute until mushrooms are soft and starting to brown. Add the wine. Turn the heat up to medium-high until the wine is simmering. Cook uncovered until only a little bit of wine is left at the bottom of the saucepan and the mushrooms are nice and saturated. Add salt and pepper to taste, I personally enjoy a good amount of both.
I eat these as a meal itself, but it'd make for a fantastic side item.
Source of recipe: I created this recipe after making a pasta sauce with red wine