Preheat the oven to 420 degrees F. Wash and peel the eggplants in stripes, keep the stems. Then pat dry. Slit the eggplants lengthwise, almost all the way down to the stem. Generously brush each with olive oil. Season with salt and pepper. Place them on an oven tray.
Roast them until tender and lightly browned, about 35 minutes.
Prepare the stuffing while the eggplants are in the oven. Heat the canola oil in a pan over medium heat. Add the onion and saute for 5-6 minutes. Add the garlic and saute for a minute. Add the tomato and oregano. Season with salt and pepper. Simmer uncovered for 5-6 minutes. Remove from heat.
Fill the eggplants equally with the stuffing using a teaspoon.
Place them in the pot. Drizzle them with a tablespoon of olive oil and 1/3 cup warm water. Cover the pot and bring to a boil. Reduce heat to medium-low and simmer covered until cooked through, about 15-20 minutes. Transfer to a serving dish. Garnish with fresh mint and serve.