Preheat the oven to 425°F.
Peel, core, and slice 8 Honeycrisp or Granny Smith apples into ¼-inch thick slices and add to a large mixing bowl.
Add ⅔ cup light brown sugar, ½ cup 100% pure maple syrup, 1 ounce lemon juice, 2 tablespoons cornstarch, 1 teaspoon vanilla extract, 1 teaspoon ground cinnamon, ½ teaspoon speculaas or apple pie spice, and ¼ teaspoon salt and toss to coat.
Add the coated apple mixture to a 10-inch cast iron skillet. If you only have an 8-inch cast iron skillet, that's okay; just reduce the apples by 1!
Cut the ¼ cup salted butter into small cubes and dot them all over the top of the apple mixture.
Top with one crust from the 1 (16 oz.) box Pillsbury refrigerated pie crusts and press the edges of the pie crust down into the pan around the edges a bit.
Brush the top of the pie crust with 1 of the 2 tablespoons milk.
In a small prep bowl, stir together 2 tablespoons granulated sugar and ½ teaspoon ground cinnamon and sprinkle the crust with half of the cinnamon sugar mixture. Repeat with the other pie crust on top of the first.
Cut 6 slits around the center of the pie crust.
Bake for 35 to 40 minutes. The filling should be bubbling around the edges, and the crust should be golden brown. I recommend checking on the crust around the 30 minute mark to make sure it's not getting too brown, if it is, I would tent some aluminum foil over the top.
Remove from the oven and immediately use a sharp chef's knife to slice across the top of the crust in lines about 2-inches apart, then slice in the opposite direction, leaving square pieces on top of the pie.
Then use a spoon to press the pieces of crust down into the filling just enough for the sauce to run over the top of the crust. This is the signature pandowdy style; the sauce will dry to create a glaze on the crust.
Let the pandowdy sit for 2 hours to cool so the juices thicken some. Then serve in a bowl with ice cream.