Heat the oven to 450°F with the rack in the middle. While the oven is getting hot, clean your mushroom caps with a brush and remove the stems. Next, brush the melted ghee on the cleaned mushrooms.
Place the prepared mushrooms gill-side down on a rimmed baking sheet lined with parchment paper. Sprinkle salt on the tops of the mushrooms.
Pop the tray of mushrooms into the oven and roast them for 12 minutes. Next, flip over the mushrooms, and roast for 5 to 10 minutes more or until the liquid released by the mushrooms has evaporated.
While the mushrooms are roasting in the oven, make the shrimp filling. Toss the shrimp, bacon, scallions, cilantro, jalapeño, and fish sauce into the work bowl of a food processor.
Pulse the ingredients for the filling until a coarsely-chopped mixture develops. The filling should be the consistency of a sticky, chunky paste. To taste for seasoning, form a tiny patty and fry it up and taste it. Then, mix in extra salt and pepper to the stuffing if needed.
Scoop out the filling with a spoon or small disher and fill each cooked mushroom with the shrimp paste.
Return the stuffed mushrooms to the oven for 8 to 10 minutes or until the shrimp mixture has cooked through. Transfer the mushrooms to a plate and serve!