Preheat the oven to 400 degrees. In a large mixing bowl with a colander, sprinkle the eggplant with a heavy pinch of salt and stir to combine. Set aside to drain. Meanwhile, over an open flame on the stove, char the outside of the bell pepper. Set the pepper over the flame and rotate every 2 minutes until completely blackened. Place in a mixing bowl and cover with plastic wrap to steam.
Place the eggplant on a baking sheet and drizzle with 1 Tbsp. oil. Place in the oven and roast until slightly browned and completely soft, about 30-40 minutes. Meanwhile, remove the skin and seeds from the bell pepper and dice the flesh. Place into a small mixing bowl with the spring onions and season with the remaining oil and vinegar along with a pinch of salt and pepper to taste. Stir until combined. Divide the eggplant between 2 plates and top evenly with the pepper relish.