Begin by cleaning and slicing fresh mushrooms into even pieces, ensuring uniform cooking. Dice one medium onion finely, and mince a couple of garlic cloves.

In a skillet, heat 2 tablespoons of butter or olive oil over medium heat. Add the chopped onion and sauté for about 4–5 minutes until it becomes translucent and slightly golden. Stir in the minced garlic and cook for an additional minute until fragrant.

Add the sliced mushrooms to the skillet. Cook for about 5–7 minutes, stirring occasionally until softened and release juices.

Sprinkle 2 tablespoons of flour over the mushroom mixture in the skillet. Stir continuously for 1–2 minutes.

Gradually pour in 2 cups of vegetable broth while continuously whisking to prevent lumps. Increase the heat to bring to a gentle boil for about 5 minutes.

Reduce heat to low and let the gravy simmer uncovered for another 5–7 minutes, stirring occasionally. Season with salt and pepper as needed.

If desired, stir in 1/2 cup of milk or plant-based cream at the end of cooking, allowing it to heat through.