Cast Iron Hot Chocolate Cake Recipe

Prepare and preheat

Preheat oven to 350°F (175°C). Place a 9-10 inch oven-safe cast iron skillet in the oven while it preheats to warm the pan. Grease a small bowl and set aside for mixing wet ingredients.

Mix dry ingredients

In a large mixing bowl, sift or whisk together 1 cup all-purpose flour, 1/2 cup unsweetened cocoa powder, 1 cup granulated sugar, 1 tsp baking powder, 1/2 tsp baking soda, and 1/2 tsp salt until evenly combined.

Combine wet ingredients

In the greased bowl (or a separate bowl), beat 2 large eggs lightly, then whisk in 1/2 cup whole milk, 1/2 cup vegetable oil, and 1 tsp vanilla extract until smooth.

Incorporate wet and dry

Make a well in the center of the dry ingredients and pour the wet mixture in. Stir gently with a spatula or wooden spoon until just combined and no large streaks of flour remain. Avoid overmixing.

Transfer to skillet

Carefully remove the hot skillet from the oven using oven mitts. Add 1 tbsp unsalted butter and swirl to coat the bottom and sides. Pour the batter into the warm, buttered skillet and smooth the top with a spatula.

Heat water and dissolve

Bring 1 cup hot water (hot but not boiling — about 190°F / 88°C) to a simmer in a kettle or small saucepan. Remove from heat and stir in 6 oz finely chopped dark chocolate, 1/4 cup granulated sugar, 2 tbsp unsweetened cocoa powder, and 1/2 tsp instant espresso powder (if using). Let sit for 1 minute to melt, then whisk until smooth and glossy.

Finish sauce

Stir in 2 tbsp unsalted butter and 1/2 tsp vanilla extract until fully incorporated. Taste and adjust sweetness if needed. Keep warm while the cake bakes.

Pour sauce over cake

When the cake has finished baking (see next section), pour the hot chocolate sauce evenly over the hot cake in the skillet so it soaks into the top and pools slightly at the edges.

Bake

Place the batter-filled skillet in the preheated 350°F (175°C) oven. Bake for 25–30 minutes, or until the cake has set at the edges and a toothpick inserted into the center comes out with moist crumbs (the center should remain slightly gooey to create a hot chocolate effect). Oven times vary—start checking at 22 minutes.

Rest briefly

Remove the skillet from the oven and let the cake rest 3–5 minutes so it firms slightly but is still hot enough to absorb the sauce.

Assemble and serve

Pour the warm hot chocolate sauce over the cake, allowing some to soak in and some to pool on top. Dust lightly with 1 tbsp powdered sugar if desired. Serve straight from the skillet with scoops of whipped cream or vanilla ice cream (about 1 cup total) alongside. For individual servings, cut wedges with a warm knife.