Heat 1 tablespoon olive oil in a large sauté pan over medium-high heat until the oil shimmers.
Add 1 pound whole small button mushrooms to the pan in a single layer if possible. Cook, stirring occasionally, until the mushrooms release their liquid, the liquid mostly evaporates, and the mushrooms begin to brown — about 8–10 minutes.
Add 3 cloves minced garlic to the pan and cook, stirring, for about 1 minute until fragrant, taking care not to let the garlic burn.
Remove the pan from the heat. Add 2 teaspoons roughly chopped fresh thyme and 1 teaspoon roughly chopped fresh tarragon.
Toss the mushrooms in the herbs until evenly coated, then serve hot.