Caramel Apple Crumb Pie

1. Make the caramel ahead

Prepare one batch of Thick Caramel Sauce (recipe below) and let it cool until it is about as thick as honey. It can be made a day ahead; bring it back to room temperature before using.

2. Prepare the crust

Heat the oven to 425°F with a rack in the lower third. Lay a Bonmat on the perforated baking sheet and set the tart mold on top. Unroll the 2 pie crust rolls onto the BonCook Pastry Mat, overlap them by about 1 inch, pinch the seam and roll into one 14-inch round, using the measurements printed on the mat as your guide. Ease the dough into the mold and let it settle into the flutes without stretching it; stretched dough pulls back and shrinks. Trim the edge even with the rim and prick the bottom all over with a fork so it doesn’t puff.

3. Freeze, then par-bake

Freeze the crust 15 minutes; a very cold crust holds its shape. Bake at 425°F for 5 minutes. Brush the warm crust, bottom and sides, with a thin coat of the beaten egg (or just the egg white) and bake 1 minute more to set it; this seals the crust against the juicy filling. Reduce the oven to 375°F and let the crust cool while you make the filling.

4. Make the filling

In a large bowl, toss the sliced apples with the granulated sugar, brown sugar, flour, cinnamon, nutmeg, salt, lemon juice and vanilla. Let stand 10 minutes to draw out some juice.

5. Make the crumb

Stir together the flour, brown sugar, oats, cinnamon and salt. Pour in the melted, cooled butter and mix with a fork until it forms moist clumps of varying size.

6. Assemble

Spread the apples evenly in the crust, mounding slightly in the center and leaving most of the pooled juice behind in the bowl. Drizzle ½ cup of the caramel over the apples. Pack the crumb evenly on top, pressing gently. Brush the top edge of the crust with the remaining egg wash.

7. Bake

Bake on the Bonmat-lined perforated baking sheet to catch any drips. After 20 minutes, lay a second Bonmat over the top of the mold like a lid to keep the par-baked crust and crumb from burning. Continue baking 25 to 35 minutes more, until the crumb is deep golden, the juices bubble thickly at the edges and a knife slides easily into the apples.

8. Cool and finish

Cool on a wire rack for at least 3 hours so the filling sets, then peel back the mold and slide the pie onto a serving plate. Just before serving, warm the remaining caramel slightly and drizzle it over the top. Finish with a pinch of flaky sea salt, if you like.

Thick Caramel Sauce

1. Dissolve the sugar

Combine the sugar and water in a heavy medium saucepan over medium heat. Swirl the pan gently, don’t stir, until the sugar dissolves.

2. Cook to amber

Raise the heat to medium-high and boil, swirling occasionally, until the syrup turns a deep amber, like an old penny, 8 to 12 minutes. Watch closely; once it colors, it moves fast.

3. Add the butter

Remove from the heat and whisk in the butter. It will foam up vigorously.

4. Add the cream

Slowly pour in the cream while whisking. It will bubble again.

5. Thicken

Return to medium-low heat and simmer 1 to 2 minutes, whisking, until slightly thickened.

6. Finish and cool

Off the heat, stir in the vanilla and salt. Cool at least 30 minutes; it thickens considerably as it cools and should be about as thick as honey before it goes on the apples.