Preheat oven to 350

Using a saute pan, heat oil on medium high heat

Add garlic and saute for 1 minute

Cut eye of round into small, bite sized chunks, and add to the garlic

Grind some salt and pepper over the top

Saute until beef is browned on all sides, but not cooked through.

Clean portabellos, and remove stem

Chop tomatoes into small chunks, and season with oregano and parsley

Mix tomatoes and feta together, and add the browned beef

Fill portabello with mixture, and bake at 350 for 15 minutes

Top with fresh basil

Serve hot