Step 1: Prepare Pickle-Brined Carrots (Optional, but Recommended). Combine the dill pickle brine and water in a small bowl. Add 1/4 cup of grated carrots to the brine. Allow to sit while preparing other components.

Step 2: Preheat Oven and Prepare Pan. For the trifle: Preheat the oven to 350°F (175°C). Spray a 13×9-inch baking pan with baking spray with flour. Line the pan with parchment paper and spray again.

Step 3: Make the Carrot Cake Batter. In a large bowl, whisk together the cake mix, oil, buttermilk, and eggs until well combined, about 2 minutes.

Step 4: Fold in Nuts and Carrots. Fold in ¾ cup of chopped walnuts and all the grated carrots (drained from the brine, if using brined carrots).

Step 5: Bake the Cake. Pour the batter into the prepared baking pan. Bake according to package directions (or until a toothpick inserted in the center comes out with a few moist crumbs, and the edges of the cake begin to pull away from the sides of the pan).

Step 6: Cool the Cake. Cool completely on a wire rack, about 1 hour. Once cool, cut the cake into 1 ½-inch pieces.

Step 7: Make the Pudding. Meanwhile, prepare the pudding according to package directions using the milk.

Step 8: Color the Pudding (Optional). Add 1 or 2 drops of red food coloring and 1 or 2 drops of yellow food coloring. Mix until the colors are well distributed and continue adding color, 1 drop at a time, until the desired orange color is reached.

Step 9: Chill Pudding. Chill for at least 30 minutes or up to overnight.

Step 10: Make the Cream Cheese Mixture. In the bowl of a stand mixer fitted with the whisk attachment, beat the cream cheese and sugar on medium-high speed until smooth and fluffy, 3 to 4 minutes. Reduce the speed to medium and gradually add the heavy whipping cream and vanilla, beating until the cream is whipped and well combined with the cream cheese, 1 to 2 minutes, stopping occasionally to scrape the sides of the bowl.

Step 11: Combine Pudding and Cream Cheese Mixture. Fold about 1 cup of the cream mixture into the pudding.

Step 12: Crush Cookies. Place the speculoos cookies in a zip-top bag and coarsely crush them with a rolling pin. Add the dill pickle powder to the crushed cookies. Set aside ¼ cup of the crushed cookies for topping.

Step 13: Assemble the Trifle. Place a single layer of cake cubes snugly in a large trifle dish (13 to 16 cubes). Top with half of the pudding mixture, sprinkle with ½ of the remaining crushed cookies, and top with half of the whipped cream cheese. Repeat the layers once more. (There may be extra cake cubes; reserve those for another use.)

Step 14: Garnish. Sprinkle the top with the reserved crushed cookies and the remaining ¼ cup of chopped walnuts. Decorate with candied carrots, if you like.

Step 15: Serve. Serve immediately.

Step 16: Make the Candied Carrots (Optional). While the cake is baking/cooling, you can make the candied carrots (if using). Preheat the oven to 225°F (110°C). Line a baking sheet with parchment paper.

Step 17: Peel Carrots. Run a vegetable peeler down the length of the carrots to make long, flat ribbons.

Step 18: Make Simple Syrup. In a medium saucepan, bring 1 cup of water and the sugar to a boil.

Step 19: Simmer Carrots. Reduce the heat to medium-low and add the carrot ribbons. Simmer, stirring occasionally, until the carrots are cooked and slightly translucent, 15 minutes.

Step 20: Strain Carrots. Strain the carrots from the simple syrup, reserving the syrup for cocktails, if you like.

Step 21: Bake Carrots. Lay the carrot ribbons out on the prepared baking sheet, making sure none are touching. Place in the oven and bake until almost dry, 20 to 25 minutes.

Step 22: Shape Carrots. Working quickly, roll the carrot ribbons around a round wooden spoon handle or a straw to create spirals.