- Stir together parsley, oil, lemon juice, garlic and thyme. Stir in salt and pepper. Set pesto aside while grilling mushrooms (or chill pesto up to 2 hr.).
- Brush all sides of mushroom caps with some of the oil floating on the pesto. Place caps, gill-side down, on BBQ preheated to medium-high. Grill 1 to 2 min. or until marked. Flip over. Grill 1 to 2 min., or until mushrooms are tender and juices start to pool in caps.
- Carefully transfer (avoid tipping out juices) mushrooms to serving platter. Spoon pesto into caps. Serve mushrooms warm.
Alternatively, cook mushrooms in skillet on stovetop on medium-high heat.
Use store-bought pesto.