Chocolate Sheet Cake - Rise and Bake with Julie

Prep:20

Cook:35

Total:1 55

Yield: squares

Equipment

Ingredients

Cake Ingredients

2½ c. unbleached all-purpose flour (RECOMMEND WEIGHING)
2½ c. granulated sugar
½ tsp. salt
½ c. salted butter
½ c. avocado oil (or neutral oil)
1¼ c. water
¼ c. unsweetened cocoa powder
½ tsp. espresso powder optional
3 large eggs
⅔ c. buttermilk
1¼ tsp baking soda

Frosting Ingredients

⅓ c. milk
1½ c. granulated sugar
5 tbsp. salted butter, softened
¾ c. semisweet chocolate chips

US Customary - Metric

Instructions

Preheat oven to 325°F (165°C). Grease a 15×10-inch jelly roll pan thoroughly (butter or nonstick spray). Optional: line the bottom with parchment.
Sift the flour through a fine-mesh sieve into a large bowl. Add the sugar and salt. Whisk 20–30 seconds to aerate and combine. Set aside.
2½ c. granulated sugar, 2½ c. unbleached all-purpose flour (RECOMMEND WEIGHING), ½ tsp. salt
In a medium saucepan over medium-low heat, melt the butter. Add the avocado oil, water, cocoa powder, and espresso powder (if using). Stir constantly until smooth and just steaming (2–3 minutes; do not boil). Remove from heat and cool slightly.
½ c. salted butter, ½ c. avocado oil (or neutral oil), 1¼ c. water, ¼ c. unsweetened cocoa powder, ½ tsp. espresso powder
In a separate bowl, whisk the 3 eggs, ⅔ cup buttermilk, and 1¼ teaspoons baking soda until smooth. To temper (recommended for extra safety): Add a small ladle (~¼ cup) of the warm cocoa mixture to the egg blend while whisking constantly. Repeat 2–3 times until the egg mixture feels warm. Then slowly pour in the remaining cocoa mixture while whisking vigorously.
3 large eggs, ⅔ c. buttermilk, 1¼ tsp baking soda
Pour the wet mixture into the dry ingredients and whisk until smooth and no dry pockets remain. The batter will be thin and pourable. Pour into the prepared pan and spread evenly (should leave about ½ inch clearance from the top edge).
Bake 30–36 minutes (check at 30 minutes). A toothpick inserted in the center should come out clean or with moist crumbs. Cool completely in the pan (~1 hour).
In a medium saucepan, combine milk, sugar, and butter. Bring to a boil over medium heat, stirring constantly. Boil exactly 60 seconds, then remove from heat. Stir in chocolate chips until fully melted and smooth.
⅓ c. milk, 1½ c. granulated sugar, 5 tbsp. salted butter, softened, ¾ c. semisweet chocolate chips
Immediately pour the warm frosting over the cooled cake. Spread quickly and evenly with an offset spatula or knife for a glossy finish (work within 1–2 minutes before it sets).
Let frosting set (~30 minutes), then cut into squares. Store airtight at room temperature for up to 2–3 days or freeze for 3 to 4 months.

Notes

Avocado oil helps maintain moisture for days while the butter adds richness.
Sift flour to prevent clumps.
Bloom cocoa gently for best flavor.
If frosting thickens while spreading, gently rewarm over low heat for 10–15 seconds.

Nutrition

Servings: squares

Calories: 324kcal