Millionaires' Shortbread

1. Preheat oven to 350°F. Line a 9-by-13-inch baking pan with foil, leaving a 2-inch overhang on long sides. Lightly grease foil.

2. Beat confectioners’ sugar and 3/4 cup butter with an electric mixer on medium speed until light and fluffy, 1 to 2 minutes. Reduce mixer speed to low and beat in almonds, flour, and 1/2 teaspoon kosher salt just until combined. Press on bottom of prepared pan. Bake until golden brown, 25 to 28 minutes. Cool on a wire rack.

3. Combine condensed milk, brown sugar, honey, 1/2 cup cream, and remaining 1/2 teaspoon kosher salt and 1/2 cup butter in a medium saucepan. Cook over medium heat, stirring constantly, until a candy thermometer reaches 236°F, 24 to 26 minutes. Remove from heat; stir in vanilla. Immediately pour caramel over shortbread. Let stand at room temperature until set, 1 to 11/2 hours.

4. Microwave chocolate and remaining 1/4 cup cream in a bowl 30 seconds; stir. Continue to microwave and stir in 10-second intervals until melted. Pour melted chocolate over caramel and spread with an offset spatula. Sprinkle with sea salt. Freeze until set, 15 to 20 minutes. Use foil overhangs to lift bars from pan. Cut into 32 squares. Store, refrigerated, in an airtight container up to 1 week.