Step 1

Thaw 1 package frozen puff pastry according to package directions, preferably in the refrigerator.

Step 2

Melt 4 tablespoons unsalted butter in a small saucepan over medium heat. Add 3 tablespoons granulated sugar, 3 tablespoons honey, 4 teaspoons heavy cream, and 1/4 teaspoon kosher salt. Bring to a boil and boil until very light in color, about 2 minutes. Remove the saucepan from the heat, add 1 cup sliced almonds and 1/2 teaspoon vanilla bean paste or extract, and stir to combine.

Step 3

Transfer to a small bowl. Refrigerate until cooled slightly and thickened to a spreadable consistency, about 20 minutes. Meanwhile, arrange a rack in the middle of the oven and heat the oven to 350°F. Line a rimmed baking sheet with parchment paper or a silicone baking mat.

Step 4

Once the topping is ready, unfold the puff pastry on a work surface. If using a puff pastry that comes in one sheet, roll it out into a 8x18-inch rectangle, dusting the work surface with flour if needed, then cut in half to form 2 (8x9-inch) rectangles. If there are two sheets, trim each one into an 8x10-inch rectangle. Place on the baking sheet, spacing them evenly apart. Using a knife, draw a rectangle on each piece 1/2-inch from the border (don’t cut all the way through). Using a fork, dock holes all over each piece.

Step 5

Gently spread the almond mixture evenly over one piece of the puff pastry, leaving a 1/2-inch border. Bake until puffed and golden all over, 30 to 35 minutes. Press the plain puff pastry sheet down if needed to create a flat surface. Let cool completely on the baking sheet. Meanwhile, make the custard filling.

Step 6

Place 2 tablespoons water in a small microwave-safe bowl and sprinkle 2 1/2 teaspoons powdered unflavored gelatin over the water and stir to mix. Let sit for 5 to 10 minutes. Microwave the gelatin mixture until melted, about 10 seconds. (Alternatively, warm over low heat on the stovetop.) Let cool slightly.

Step 7

Place 1 cup cold heavy cream in a large bowl. With an electric hand mixer on medium speed, slowly add the melted gelatin. Once incorporated, increase the speed to medium-high and whip until soft peaks form, about 1 1/2 minutes. (Alternatively, beat with the whisk attachment in a stand mixer on medium speed or whisk by hand.)

Step 8

Place 1 1/2 cups cold whole milk, 1 (3.4-ounce) box instant vanilla pudding, 1 teaspoon vanilla bean paste or extract, 1/4 teaspoon kosher salt, and 1/4 teaspoon almond extract if desired in a medium bowl. Beat with an electric hand mixer on medium speed until completely smooth, about 2 minutes (or beat by hand). Transfer to the bowl with the whipped cream and beat with an electric mixer on medium speed until smooth and stiff peaks form, 1 to 2 minutes. If the puff pastry is not cooled yet, refrigerate in an airtight container.

Step 9

Dollop the custard filling onto the plain pastry and spread into an even layer. Top with the almond puff pastry almond-side up. Cover lightly with aluminum foil and refrigerate for at least 2 hours or up to overnight.

Step 10

Transfer to a cutting board. Use kitchen shears to cut the top layer of pastry in a 3x4 grid to create 12 pieces, then follow those lines to cut through the pastry cream and bottom pastry with a knife, wiping the knife clean after each slice for the cleanest-looking slices.