Stuffed Portobello Mushrooms - "The Roof Restaurant"

Ingredients:

1/2 c. diced red onion
1 clove garlic, minced
1/4 c. unsalted butter
1/2 c. diced yellow squash
1/2 c. diced zucchini
1/2 c. diced eggplant (I leave this out)
1/4 c. diced Roma tomatoes
1/4 c. tomato puree (I leave this out)
Salt & pepper to taste
6 Portobello mushrooms
2 Tbsp. olive oil
1/4 c. Asiago cheese 

Directions: 

Remove the stem and ribs from the Portobello mushrooms then lightly brush mushroom with olive oil. Saute onion and garlic in the butter until onion begins to brown. Add the squash, zucchini, and eggplant and sauté until the squash is tender, but don't let it cook too long. I chop up the mushroom stems and add them to the saute.  Add the Roma tomatoes and the tomato puree. Adjust the flavor with salt and pepper. Remove from heat and set aside.

Spoon about ½ cup of the squash mixture into each mushroom and sprinkle with Asiago cheese. Bake in a 350 degree oven for 12-15 minutes or until the cheese become golden brown.