Preheat oven to 350°F

Line a rimmed baking sheet with aluminum foil and set aside

Prepare an ice water bath by placing ice cubes into a large bowl of cold water

Bring a large pot of water to a boil

Add zucchini and boil 6 to 8 minutes, just until softened slightly

Remove zucchini from boiling water; plunge into ice water bath to cool

When cool, remove zucchini from the ice bath and place on a paper towel-lined plate

Heat oil in a large skillet over medium heat

Add onion, mushrooms, garlic, oregano, salt and pepper; sauté until soft, 5 to 7 minutes

Stir in tofu, if desired

Remove from heat and set aside

Cut zucchini in half lengthwise

Use a teaspoon to scrape out seeds, making a long well

Chop pulp and place in a fine-mesh sieve; use a spoon to press out excess liquid

Mix pulp into the onion-mushroom mixture

Place the hollowed out zucchini halves on the prepared baking sheet

Fill evenly with onion-mushroom mixture

Top with cheese

Combine breadcrumbs and paprika; sprinkle lightly over zucchini (you may have some crumbs left)

Bake until the topping is golden brown, 12 to 15 minutes

Serve topped with chopped parsley