Preheat oven to 400-425 degrees. Take the butter and melt it over medium heat in a skillet. Once melted, add the garlic. The garlic will start to smell after about 2 minutes, then add half of the chopped onions and all of the bell peppers. Sautée for about 7 minutes then set aside to cool down. Next in a large bowl, take the cream cheese, garlic powder, half of your chopped parsley, salt, basil, bread crumbs, remaining green onions and crabmeat and mix together wit a wooden spoon or spatula. Once mixed, add the sautéed bell peppers and onions to the mix. Blend all the ingredients evenly. The finished mixture shouldnt be too sticky to the touch. it should be fairly easy to spoon or manipulate with the fingers. You may add more bread crumbs if desired. Next, brush the mushrooms with olive oil, arrange them in a pan and fill them with the mix. Once all of the mushrooms are filled, top them with the remaining parsley. Put the mushrooms in the oven for about 15-20 minutes (oven temps vary) watch them closely during this time. Once they start to brown, take them out and serve. Please note that there may be some mix remaining, this can be frozen a saved for a later date or refridgerated for up to 4 days.