1. In a saucepan, melt the butter over medium heat. Stir in brown sugar until dissolved. Slowly whisk in the heavy cream and simmer for 5–7 minutes until thickened. Stir in vanilla and a pinch of salt, then set aside to cool slightly.

2. In a large bowl, toss sliced apples with lemon juice, cornstarch, cinnamon, nutmeg, and a few tablespoons of the toffee sauce. Mix well to coat.

3. Preheat oven to 375°F (190°C). Roll out the bottom crust into a 9-inch pie dish. Add the apple mixture, pressing it down slightly to pack tightly. Drizzle with additional toffee sauce.

4. Roll out the second crust and cut into strips. Create a lattice top, trim excess dough, and crimp edges to seal.

5. Brush the lattice and crust edges with beaten egg and sprinkle with coarse sugar.

6. Bake on a baking sheet for 45–55 minutes until golden brown and bubbly. Cover loosely with foil if the top browns too quickly.

7. Cool the pie for at least 2 hours before slicing to allow the filling to set properly. Serve warm with more toffee sauce or ice cream if desired.