marinate: A sauce made of oil, vinegar, spices, herbs, etc., in which meat, fish, or other food is soaked before cooking to flavor or soften it(Wikipedia)
John made an excellent portobello mushroom salad a while back which I took and modified slightly. The key to this dish is to marinate the portobello mushroom with a splash of balsamic vinegar before grilling.
Grilled Portobello Mushroom
1 large portobello mushroom
Begin by cleaning the mushroom with a damp paper towel or mushroom brush. Remove the stem by giving it a firm twist. Finely chop up the shallot and mix in the balsamic vinegar. Place the mushroom cap side up and drizzle the mixture evenly over the mushroom. Feel free to brush the mixture on to coat it evenly. Allow the marinate to sit for a couple hours before grilling. Over a hot grill, grill the mushroom, cap side up for approx. 10 minutes. Remove from heat and allow to cool. Slice and plate, adding slices of tomatos and boccocini between the slices. Sprinkle chopped dill on top and add additional boccocini cheese and tomatos for garnish.