Prep the ingredients per the instructions above.

Make the apple sauce: place the apples, water, sugar, cinnamon, and allspice into a saucepan over medium heat. Bring to a simmer and cook until the apples are very soft. Remove from the heat. Mash the apples with a potato masher or pulse them in a blender for a smoother consistency. Then set aside.

Preheat the oven broiler on low.

Add the tomato, pesto, garlic, and oregano to a blender. Blend until fully combined. Season with salt and pepper to taste.

Lightly toast the bread. Then set aside.

Heat the oil in a saute pan on medium heat. Saute the mushrooms until golden brown and softened. Set aside.

Spread the sauce onto the bread, covering it well. Evenly distribute the cheese, onions, and mushrooms.

Place on a foiled-lined baking sheet under the broiler until completely melted. (Keep a watchful eye while using the broiler.)