Prepare the ice cream. Beat the cream and malted milk powder until you have stiff peaks. Fold in the condensed milk, salt, cinnamon, vanilla, and bourbon. Transfer to a standard 8 ½x 4 ½ inch loaf pan, wrap with plastic wrap, and freeze until firm, at least 6 hours.

Prepare the pie crust. Mix together the flour, sugar, and salt. Add the butter and toss to combine. Smoosh each of the butter pieces flat. Then, make a well in the center and add ¼ cup water. Toss to combine. If everything is evenly moistened and you can press the crumbs together, then you don’t need any more water. Add a little bit at a time until the dough holds together. Form the dough into a disc and wrap with plastic wrap. Refrigerate for at least 30 minutes.

On a lightly floured surface, roll the disc out into a large rectangle. Fold the dough in half, top down. Then bring the left side over to the right. Wrap and refrigerate for another 30 minutes to an hour.

Repeat the folding and resting process one more time.

Heat the oven to 375°F with a rack in the lower third of the oven.

On a lightly floured surface, roll the dough into a 10 inch circle. Fit it into a standard 9-inch pie plate (ideally glass) and crimp the edges as you like. Cover with plastic wrap and refrigerate while you make the filling.

In a large bowl, beat together the butter and the sugars until creamy. Add the egg and vanilla and mix to combine. Add the flour, baking soda, and salt and stir to combine. Stir in the chocolate and nuts, but reserve a bit for the top.

Spread the filling into the prepared pan. Top with the remaining nuts and chocolate. Bake until the center is puffed and set and the underside of the crust is golden brown, 35 to 40 minutes. Let stand for at least 15 minutes before serving with a big scoop of ice cream.