Stuffed Mushrooms is a dish that I make regularly.
Field mushrooms are plentiful (and affordable) at certain times of the year and when they are, its stuffed mushroom time.
Fillings vary depending on what I have at hand and mushrooms are so forgiving that you can afford to experiment a bit so don’t be scared.

The mushrooms I used for this were huge. I don’t like to think where they came from and what led them to be the size they were but it was winter and I was looking for something different. They were about 6 inches (15 cm) in diameter.

I made a duo of fillings as we (husband and I) were divided on what we wanted, so we split them and had the best of both worlds.

Stuffed mushrooms are easy to make ahead and pop into the oven when you need them.
They will also last in the fridge for a day or two before cooking as well

For the Blue cheese and Feta: try to find a cheese that is not too salty like Roquefort. I used a creamy blue d’Auvergne.
The feta is salty enough in it’s own right and too much will ruin the balance.
If you’re looking to add some freshness in with the cheeses you could always add some chopped celery, peppers and maybe even a dried raisin or two.

For the Balsamic Onion and Thyme: more thyme is a good thing; it really works with the balsamic. You can always drop some minced garlic into the mix and if you’re looking for a dreamy finish top it off with a dollop of cream cheese mixed with cracked black pepper.