Prepare your chanterelle mushrooms. Clean mushrooms to cut off spoiled parts. Rinse if they are dirty, if they are not too dirty just use a brush to brush off dirt. Pat dry wet mushrooms to take in excess waters.
Cut your mushrooms into two or fours if they are large, or else leave whole.
Heat up a skillet with the butter and saute sliced onion until soft.
Add mushrooms to your pan and keep over a high to medium heat setting.
Season with salt and black pepper to taste. Add thyme and combine.
Stir occasionally while the mushrooms are reducing. The mushrooms will lose a lot of liquids and that's ok.
Cook until mushrooms are done over medium to high heat and until you are satisfied with the result.
Serve still warm as a side dish.
The prepping time can be more if your mushrooms are muddy and small.