Preheat the oven to 375 degrees farhenhiet

Place the stemmed mushrooms on a foil-lined baking sheet. IN a large skillet, sauce the onion and the sausage over high heat until the sausage is cooked through, about 8 minutes.

While the sausage is cooing, puree the mayonnaise, chiptole pepper and adobo sauce in a blender or food processor. Once the sausage is cooked through, remove from the heat and stir in the chipotle mayo. Spoon he filling into the mushroom caps, being careful not to overfill. Bake for 20 - 25 minutes, or until the stuffing starts to brown nicely along with the mushrooms.