1- First, preheat your oven to 375°F (191°C) to get things warm and ready.

2- Next, combine the 3 tablespoons of softened unsalted butter with 1/4 cup packed brown sugar, 1/2 teaspoon ground cinnamon, and 1/8 teaspoon ground nutmeg. Beat or mash them until smooth, then stir in 1/4 cup old-fashioned oats and any optional 2 tablespoons of raisins, dried cranberries, or chopped nuts for extra flavor.

3-Core the apples: Use a sharp paring knife and spoon to remove the seeds, going about halfway to three-fourths down into each of the 4 large apples.

4- Place the cored apples in an 8- or 9-inch baking dish.

5- Fill each apple with the oat mixture, packing it gently inside.

6- Pour 3/4 cup of warm water around the apples in the dish to keep them moist during baking.

7- Bake for 40-45 minutes until tender, but still holding shape; add more time for softer apples.

8- Once done, let them cool a bit and serve warm with options like whipped cream or ice cream. If you like, baste the apples with the pan juices for added moisture.