Clean the mushrooms with a damp paper towel and remove the stems. Set aside mushroom caps and stems.
Chop the stems finely and add them to a pan with 1 tablespoon of butter and garlic. Sautee until fragrant for about 2 minutes.
Add the wine and let it cook down completely, about 1 minute.
Add the spinach and let it wilt. If you need more liquid add a splash of water or vegetable broth.
Remove from the heat and add the Boursin cheese mixing well with a spoon until well incorporated.
Melt a tablespoon of butter and combine it in a bowl with the panko and parmesan cheese.
Add the cheese and mushroom mixture to the mushroom caps and top with the panko and parmesan topping.
Bake at 375 Fahrenheit for 15 minutes. Broil on high for 2 minutes until the panko is golden brown.
Garnish with chives and serve.