I wipe each mushroom down with a damp paper towel instead of rinsing them under water, since mushrooms soak up moisture fast and that leads to soggy caps. Gently twist or cut out the stems, then set the caps aside on a tray. Finely chop the stems — you'll use most of that for the filling, so don't toss them.
I heat one tablespoon of olive oil in a skillet over medium heat and toss in the chopped mushroom stems and minced garlic. I cook this for about 4-5 minutes, stirring occasionally, until the mixture turns golden and the liquid has mostly cooked off. Let it cool slightly before mixing it into the cheese.
In a mixing bowl, I combine the softened cream cheese, parmesan, breadcrumbs, parsley, salt, and pepper with the cooled mushroom-garlic mixture. I stir until everything is evenly combined and the filling looks thick but spreadable, not runny.
Using a small spoon, I fill each mushroom cap generously, mounding the filling slightly above the rim. I like to press it in gently so it doesn't fall apart once baked. Arrange the stuffed caps on a parchment-lined baking sheet in a single layer.
I brush the outside of each mushroom lightly with the remaining olive oil, then bake at 375°F for 20-22 minutes, until the tops are golden and the mushrooms release a little liquid around the edges. Let them rest for 2-3 minutes before serving so the filling sets slightly.
Right before serving, I sprinkle fresh parsley over the top and add an extra pinch of parmesan while they're still warm. This little finishing touch makes the tray look like it came straight out of a restaurant kitchen.