Carrot Sheet Cake

All-purpose flour: 300g (0:42)
Cornstarch: 18g (Aaron's secret to mimicking soft cake flour) (6:11)
Vegetable oil: 350ml (or 1.5 cups) (2:44)
Brown sugar: 220g (3:12)
Granulated sugar: 200g (3:19)
Large eggs: 4 (3:19)
Grated carrots: 313g (4:49)
Vanilla paste: 2 tbsp (4:23)
Baking powder: 7g (1:14)
Baking soda: 5g (1:14)
Fine sea salt: 1/2 tsp (2:06)
Cinnamon: 1 tsp (2:18)
Ginger: 1 tsp (2:18)
Ground nutmeg: 2 tsp (8:15)
Ground cardamom: 1.5 tsp (8:33)
Golden raisins: 100g (Added by special request) (0:15)
Mixed nuts: 100g total (A 50/50 blend of chopped hazelnuts and walnuts) (4:49)

Cold cream cheese: 440g (11:23)
Butter: 250g (Slightly chilled, but soft enough to leave a thumbprint) (11:59)
Powdered sugar: 400g (Adjusted down from 600g for perfect sweetness) (13:21)
Vanilla paste: 1 tsp (12:50)
Walnuts: An extra generous handful (Roughly chopped for topping) (17:12)

Preheat your oven to 350°F (175°C) (10:31). Take a standard 9x13-inch baking dish and line the entire bottom and sides completely with parchment paper (4:17). Use kitchen shears to snip the corners so the paper folds and lays perfectly flat (9:54).

Set up your kitchen scale (0:50). Weigh out and whisk together 300g of all-purpose flour, 18g of cornstarch, 7g of baking powder, 5g of baking soda, and 1/2 teaspoon of fine sea salt (0:42). Whisk in your dry spices: cinnamon, ginger, nutmeg, and cardamom (2:18).

Pour 350ml of vegetable oil directly into the bowl (2:36). Add the brown sugar, granulated sugar, four eggs, and 2 tablespoons of vanilla paste (3:12). Add your 313g of freshly grated carrots, the 100g nut blend, and the golden raisins (4:49).

Mix everything together gently using a hand spoon or spatula (5:14). Scrape the absolute bottom of the bowl and drag it up to ensure no dry pockets remain (7:19). Do not use an electric mixer here; carrot cake batter is incredibly easy to over-mix! (5:14)

Pour your smooth, rich batter into your fully lined 9x13 pan (10:23). Bake at 350°F (175°C) for exactly 30 minutes (10:31). Let the cake cool completely before attempting to frost it.

While the cake cools, place 440g of cold cream cheese and 250g of slightly chilled butter into a clean bowl (11:23). Mix on a low speed with a hand mixer to combine them (12:19). Blend in 1 teaspoon of vanilla paste and 400g of powdered sugar until the texture is completely smooth (12:50).

Pour your cream cheese frosting smoothly over the top of the sheet cake (15:01). Use your spatula to create texturized, elegant "sideways swoops" in the frosting while ensuring no cake peeks through (16:25). Roughly chop a handful of walnuts into large, chunky pieces and sprinkle them generously over the top (17:20).