Remove any stem from caps. Mince stems and set aside.
Place oil in skillet over med heat, add quinoa and garlic. Toast them well.
Add the chopped mushroom stems and kale. Stir frequently.
As soon as kale is wilted, add stock and thyme.
Reduce heat to low-med. Cover and simmer until stock is absorbed and kale is tender (about 25 minutes).
Preheat oven to 375 degrees.
Generously pack quinoa mixture into the mushroom caps. Mixture will not be sticky, but gently pressing will hold it together.
Spray bottom of baking dish with non-stick cooking spray.
Arrange mushrooms in dish. Bake for 15 minutes, then add about tablespoon of water* to bottom of dish, and bake another 5 minutes.
Sauce
Melt butter over med heat. If using flour, mix into the melted butter.
Add the buttermilk and blue cheese. Stir frequently.
If using flour: Sauce will be done when blue cheese is melted and sauce has thickened a little. Cook a minimum of 5 minutes, reduce heat if necessary. You must make sure flour is cooked.
If not using flour: Whisk sauce over medium heat until blue cheese is melted, then cook an additional minute. Remove from burner and allow to cool and thicken slightly before pouring.
Notes
*Ensures caps don't dry out, but will evaporate quickly
**Thickens sauce, but if you are on a gluten-free diet skip it, just allow sauce to cool a little before pouring, so it will thicken slightly.