Preheat oven to 375. Slice zucchini in half, lengthwise and scoop out the insides where the seeds are making enough room to fill with topping. (Careful not to go too deep and rip the skins). Chop insides into small chunks. Reserve the halves and the insides.Heat coconut oil in a pan on medium heat and sauté onions for 1-2 minutes until slightly transparent.Add mushrooms and sauté for 2 minutes more.Add celery and garlic and 1 cup of chopped zucchini flesh and cook down for 2-3 more minutes.Stir in basil and rosemary and cook 1 minute more.Remove from heat and transfer to bowl. Add tempeh crumbles and butter and allow to rest until room temperature.Once the mixture has cooled, add beaten egg, shredded cheese, salt and pepper.Fill cored zucchini with mixture.Fill glass casserole dish with â…› inch of water and place zucchini boats in dish.Bake 35-40 minutes until golden brown.