Preheat the oven to 375 degrees F. Heat the oil in a large skillet and saute onion until it begins to turn translucent. Remove from heat and stir in liquid smoke. Toss corn in mixture to coat and then transfer to a baking sheet. Roast for a few minutes until golden brown, then remove and set aside. Bring stock to a boil in a large pot and add potatoes. Reduce heat to medium and cook until fork tender. The potatoes will absorb some of the liquid. Stir in onion and corn mixture and season with salt and pepper, to taste. Let simmer until stew like consistency. Garnish with scallions.