Preheat the oven to 350 degrees
Finely chop onion, jalapeno, and celery stalks and combine in a bowl
Using a small pan on medium heat add 1 tbsp of olive oil and cook the sausage
Once the sausage is cooked combine with the veggies in the bowl and transfer back to the small pan
Let the ingredients simmer on low heat for 5 minutes
On a large baking sheet -- place all the mushrooms (stems gone) with distance between them
Take 1-2 tbsps of olive oil and lightly coat the mushrooms
Using a spoon, take your sausage mixture and stuff the mushrooms. I normally have fallout and I let that cook regardless. Always good to have more mix!
Place in oven for about 10 minutes or until tops of mushrooms look wrinkly
Remove and serve!