My chocolate pound cake is rich and chocolatey with an irresistible velvety crumb. The only thing that makes it better is a fresh strawberry buttercream that tastes exactly like strawberry ice cream. When strawberries are in season I always opt for fresh, but frozen strawberries will work just as well in this recipe.
Position a rack in the center of the oven and preheat to 350 degrees F. Coat an 8-by-4-inch loaf pan with nonstick spray and line with parchment paper to cover the bottom and long sides. Lightly spray the parchment. Set aside.
For the cake: Whisk together the hot water and cocoa powder in a large liquid measuring cup until it forms a smooth, thick paste. Add the oil, eggs and vanilla and whisk until combined and smooth.
Mix the flour, sugar, baking powder and salt in a stand mixer fitted with the paddle attachment to combine. Add the butter and 1/3 of the chocolate-egg mixture to the dry ingredients. Mix on low speed until incorporated, about 30 seconds. Raise the speed to medium-high and beat until combined, about 30 seconds. Scrape the sides of the bowl clean with a rubber spatula and beat 30 seconds more. Add the remaining liquid ingredients in 2 additions, scraping and beating 20 to 30 seconds after each addition. Scrape the bowl clean one last time and beat until fluffy, about 10 seconds.
Fold in the chocolate chips if using and pour the batter into the prepared pan. Tap the pan several times on the counter to release any air bubbles. Bake in the center of the oven until a toothpick inserted in the center comes out with moist crumbs, 1 hour 2 minutes to 1 hour 8 minutes.
Cool the cake in the pan on a wire rack about 15 minutes. Loosen the edges of the cake from the pan with a metal spatula. Remove the cake from the pan and cool on the rack for an additional 15 minutes. Place the cake back in the pan, wrap with plastic wrap and allow to cool completely before frosting, about 6 hours.
For the buttercream: Bring the strawberries, sugar and 1 tablespoon water to a simmer in a small saucepan over medium heat. Stir and smash the strawberries with a rubber spatula, making sure that they don’t stick to the pan. Simmer while stirring to reduce and thicken slightly, 3 to 4 minutes. Strain the strawberry puree through a fine-mesh sieve into a bowl, pushing the purée through the sieve. You should have 3 tablespoons purée. Cool the purée 15 to 20 minutes.
Beat the butter in a stand mixer fitted with the paddle attachment on medium-high speed until smooth and shiny, 1 to 2 minutes. Add the confectioners’ sugar and vanilla and beat on low speed until it forms a paste. Scrape the sides of the bowl and paddle clean and beat on high speed for 1 minute. Reduce the speed to low, add half of the strawberry purée and mix to combine. Beat on medium speed for a few seconds, then add the remaining puree. Stop and scrape the sides of the bowl and beat on high speed until smooth, 2 to 3 minutes.
If the buttercream looks separated, scoop about 1/4 cup into a microwave-safe bowl and heat until melted, 5 to 6 seconds. Add this melted buttercream back into the bowl of buttercream and beat on medium speed until the mixture is smooth.
To frost the cake, trim off the baked crust on the short ends of the cake and trim off a bit of the crown, if desired. Dollop the buttercream on top and spread to the edges, smoothing as desired. Store any leftovers covered on the counter for up to 3 days.
The butter must be softened enough to spread. If the butter is too firm, microwave it 3 to 4 seconds to soften. Wrapping the cake while it is warm traps steam moisture and ensures a tender, even crumb for the finished pound cake.