Rub 1T on all 4 portabella mushroom caps, sprinkle lightly with salt and pepper. Set aside.
Toss carrots in 2T olive oil, salt, pepper, thyme. Arrange in single layer on baking sheet lined with parchment paper, but leave room.
Bake at 425 for 20 minutes
After 20 minutes, place portabella mushrooms on the same baking sheet. Bake an additional 10 minutes.