Using a 12-inch Lodge cast-iron skillet, heat the butter and canola oil over medium heat. Add the lemon juice, apples, and brown sugar. Dissolve the cornstarch in the hot water, stir with a spoon. Add the dissolved cornstarch to the apple mixture. Cook over medium to high heat for until the apples are slightly softened, about 10-15 minutes. Stir occasionally with a wooden spoon. Remove from the heat and sprinkle with cinnamon and nutmeg. Stir to combine.

To make the cobbler topping, sift the flour and baking powder into a large bowl. Add the maple sugar, granulated sugar, salt and stir. Cut the butter into small pieces and cut into the flour mixture with either two forks or a pastry cutter. You want the pieces to resemble coarse cornmeal. Stir in the beaten egg, vanilla and buttermilk, just until it is combined.

Scoop the topping evenly over the apples.

Bake in a preheated 375 degree F oven for 30-35 minutes. Or until golden brown and the apple filling is bubbling over. Place a half sheet pan lined with parchment paper on the rack below the pan, to catch any juices that may bubble over.

Let cool slightly before serving. Serve with vanilla ice cream or whipped cream.