In a baking dish that will adequately fit the apples, add the maple syrup, only 2 tablespoons (28 g) of brown sugar and the apple cider, stir to combine. Add 1 tablespoon (15 g) of butter to the baking dish and set aside.
Use a paring knife or a melon scoop to core the apples, keeping the bottoms of the apples intact. Discard the seeds and roughly chop-up any edible parts from the core, set aside.
Peel the top 1/4 -inch (3.6-cm) of the skin from each apple (don’t forget to do this, otherwise the skins will bubble and burst).
In a separate medium bowl, combine the cinnamon, pinch of nutmeg and 1/4 cup (55 g) of brown sugar, stir to combine. Add the chopped apples and gently mix to incorporate. Lightly spoon the mixture into the hollows of the apples, leaving about a 1/2-inch (1.2-cm) or so from the top.
Add 2 teaspoons of the pan sauce into the stuffed apples, making sure to also brush the pan sauce on the exposed parts of the apples, too. Quarter 1 tablespoon (15 g) of butter and dot the top of each apple.
To make the crumble topping combine the flour, sugar and 3 tablespoons (45 g) of chilled butter (cut into small cubes). Cut the butter into the mixture by pressing it down with a fork and stirring it into the flour and sugar. Keep repeating this process until the mixture resembles coarse sand.
Lightly spoon the crumble on the top of each cored apple.
Nestle the apples into the baking dish with the pan sauce and bake until tender when pierced with a fork. Depending on the size and type of the apples used this can take about 45-60 minutes, or longer if you like a softer Apple. Apples should be tender when done, not mushy, and should still require the gentle push of a fork or spoon to eat. To serve, add as little or as much pan sauce as desired around each individual apple. Enjoy them hot, room temperature or chilled.