Preheat oven to 350°F. Add water to a 9" x 9" baking dish or small, rimmed baking sheet until it reaches a depth of ½" of water. Set aside.

Wash apples; pat them dry with paper towels. If necessary, cut a very thin slice off the bottom to ensure the apples will be sit level in the baking dish.

Use apple corer (or sharp knife to remove the apple core and seeds, but make sure you don't cut all the way through the bottom. You want the filling to stay IN THE APPLE! Once you have removed the core/seeds, widen the opening more, to hold more filling. You can use a spoon for this, because it's safer than using a sharp knife! Set apples aside.

In a bowl mix melted butter, brown sugar, cinnamon, a tiny pinch of salt, chopped pecans (or walnuts), and flour. Stir until it becomes a thick, streusel-like mixture. This is the filling for the cored apples.

Divide filling evenly between the 2 apples, pushing it deep into the hollowed-out core. Pack or pile the filling on top of the apples (if necessary) to use all the filling. Place apples into the prepared baking dish (set them in the water).

Place baking dish in preheated oven. Bake apples (uncovered) at 350°F. for 35-40 minutes. NOTE: Baking time may vary slightly, based on the size, variety or ripeness of apples used. I recommend checking them at the 30-minute mark, then keep an eye on them until done. When done, filling should be nicely browned, and a butter knife (or even a toothpick!) can easily be inserted into the apple. The baked apples must be tender all the way through!

Transfer apples out of dish with a metal spatula; cool slightly before serving. Serve warm, with a scoop of vanilla ice cream (if desired) and enjoy!