Combine mushrooms, thyme, parsley and 1 tablespoon olive oil in a sealable plastic bag. Add fresh pepper and shake to distribute the seasonings. Use a vacuum sealer to remove the air and seal the bag.
Attach a sous vide precision cooker to a large pot filled with water and set temperature to 175 degrees F (79°C). Lower the sealed bag into the water and submerge. Set timer to 30 minutes. If you don't have a sous vide rack, use stainless steel tongs to hold the bag in place.
Meanwhile, heat 2 tablespoons olive oil in a nonstick skillet over low heat and add sliced garlic. Cook for 10 minutes to infuse oil. Remove from heat until mushrooms are finished cooking.
When mushrooms are finished cooking, heat garlic oil over medium-high heat. Scoop mushrooms out of the bag using a slotted spoon and saute in garlic oil for 3 to 4 minutes. Season with salt to taste.
