Start by rolling out your pie crust to form an 11-inch circle. Place it gently into a 9-inch pie plate. Don’t worry if it doesn’t look perfect—this pie is all about love. Crimp the edges using your fingers to create a lovely border. Once that’s done, pop the pie plate into the freezer while you whip up the filling.

Next, let’s get that oven cozy! Preheat it to 400°F (200°C). This temperature works wonders for getting that top crumble nice and crispy.

Time to tackle those apples! Peel and slice the Granny Smith apples into ⅛-inch thick slices, discarding the cores. If you have an apple peeler/corer, this can be done in a jiffy! Toss the sliced apples in a large bowl along with the granulated sugar, flour, cinnamon, lemon juice, and ground nutmeg. Mix everything thoroughly to ensure each slice is coated evenly, then set it aside to let those flavors mingle.

In a separate mixing bowl, whisk together the all-purpose flour, rolled oats, brown sugar, granulated sugar, cinnamon, and sea salt. Next, add the softened butter—this is where the magic happens! Use a pastry cutter or your hands to integrate the butter into the dry ingredients until you achieve a crumbly texture.

Take the pie crust out of the freezer; it should be firm to the touch. Now, it’s time to pile in those apples! Dump the coated apple mixture into the crust, mounding it high in the middle. Don’t be shy—you want that filling to be generous! Gently press the crumble topping down over the apples. This will help it hold its shape during baking.

Place the pie in the oven's middle rack with a large baking sheet on the lower rack below to catch any drippings. Bake at 400°F for the first 20 minutes, then reduce the heat to 375°F and continue baking for an additional 30 to 40 minutes. Keep an eye on the pie’s crust and topping; if they start turning golden brown too quickly, cover them with aluminum foil to prevent burning.

Once baked to perfection, take the pie out of the oven and allow it to cool for at least three hours before slicing. This cooling step is vital. It allows the filling to set, making serving so much easier. And let’s be honest, there’s no better way to enjoy this pie than with a scoop of vanilla ice cream on top!