Preheat oven to 400℉. Gather the ingredients so that you have everything close at hand on the counter or table.
Prepare the Apples
Using a pairing knife, core, peel, and thinly slice the apples. Place slices in a large bowl and sprinkle lemon juice on the apples. Mix well to coat.
If desired, you may also chop the raisins so that they are smaller.
Make the Irish Cream Sauce
In a small saucepan, melt butter over medium heat. Add the brown sugar, stirring constantly until the mixture thickens and pulls away from the sides of the pan. This may take 1-2 minutes.
Remove pan from heat and stir in the Irish cream liqueur and ground cinnamon.Adding the Irish cream liqueur to the hot butter mixture will cause it to bubble up in the pan. Do not be disturbed by this. All is well.
Return the pan to medium heat, and continue stirring until the sugar has completely dissolved, 30-40 seconds. Set aside and allow the sauce to cool and thicken while you prepare the pastry dough.
Prepare the Dough
To make the pie dough, mix together the all-purpose flour and salt.
Then cut in the shortening with a blending fork or pastry blender. Once the mixture resembles coarse crumbs, add cold water and finish mixing until the dough forms a ball when stirred.
Assemble the Slab Pie
Roll the dough out onto a floured surface to a 10″ x 20″ rectangle or oval. Transfer the dough to a baking sheet lined with parchment paper or a silicone baking sheet.
Arrange the apple slices in a pretty pattern beginning in the center and working outward, leaving at least two-inches free on the outer edges. Sprinkle raisins on top of the apples, as desired.
Fold edges up around the apples, leaving no openings in the corners. Brush pastry edges with 2 tablespoons of Irish cream and sprinkle with turbinado sugar.
Pour thickened Irish cream mixture over the apples, being careful not to get any on the outer crust. The sauce should cover the area of the pie, but should not seep outside the crust.
Bake in a preheated oven for 25-30 minutes, until the pastry is lightly browned and the apples are tender. The sauce should be hot and bubbly. Remove from oven and allow to cool for 12-15 minutes before serving.
Serve this slab pie with whipped cream or scoops of vanilla ice-cream. Serves 10-12.
Notes
*Unless otherwise indicated, all butter used on this recipe site is salted.