Herbs: Rinse and dry the parsley and the oregano, and remove the leaves from the stems. Chop the herbs into a fine texture.
Garlic: Remove the skin from the garlic. Chop finely, or I like to use a garlic press.
Serrano Pepper: Remove the seeds from the pepper and finely dice.
In a medium bowl or jar, combine the onion, parsley, oregano, garlic, salt, and red pepper. Add the oil and vinegar and mix well.
Store covered for a couple of days and use before the herbs start to turn brown.
Salt and pepper the chicken thighs.
Cut the potatoes into quarters.
Place the potatoes into a pot of water, bring to a boil. Reduce the heat to a gentle boil and cook them until they are soft. (Test with a toothpick or fork for doneness.)
Drain in a collander. Let cool for about 10 minutes and then peel off the skins with your fingers.
Mash with a potato masher or press the potatoes through a ricer.
Add the butter and goat cheese. Mix together. You may have to reheat the potatoes if the butter and cheese aren't melting.
Add the broth a little at a time to thin the mashed potatoes to your desired thickness.
This recipe makes about 1 cup of Chimichurri Sauce.Food Processor InstructionsAdd all ingredients to the bowl of a food processor. Pulse until ingredients are finely minced.Make AheadYou can make Chimichurri Sauce up to 4 days ahead.Mix all of the ingredients together in a Mason jar, but then do not add vinegar until the day that you will be serving the chimichurri.