Ingredients
Equipment
Method
Preparing Your Oven and Pan
- Preheat your oven to 350°F (175°C). Thoroughly butter a 10-inch springform baking pan and dust it generously with unsweetened cocoa powder to prevent sticking and add flavor.
- Pour the Guinness beer into a glass or cup and let it rest for about 5 minutes to allow the foam to dissipate and carbonation to release, ensuring a more stable batter.
Melting and Mixing the Wet Ingredients
- Pour the room temperature Guinness into a large saucepan. Add the sliced butter and heat gently over medium heat until the butter is completely melted.
- Whisk in the cocoa powder and granulated sugar until fully incorporated and dissolved, creating a dark and glossy mixture.
Combining Wet and Dry
- In a small bowl, beat the sour cream, large eggs, and vanilla extract until creamy and smooth.
- Carefully pour this mixture into the buttery beer batter, whisking until everything is completely smooth.
- Finally, whisk in the all-purpose flour and baking soda. Fold in the ½ cup (3 oz/85g) of finely chopped 70-85% dark chocolate until just combined. Avoid overmixing to prevent a tough cake; a few small lumps are acceptable.
Baking the Cake
- Pour the batter into your prepared springform pan. If the pan seems very full, place it on a half sheet pan as a safeguard against spillage.
- Bake on the center rack for 45 minutes to 1 hour. Check for doneness by inserting a cake tester or toothpick into the center; it should come out clean or with only moist crumbs. The cake should also feel springy when lightly touched. Remove from the oven once baked.
Cooling the Cake
- Allow the cake to cool completely in the springform pan on a cooling rack. This is crucial for its structural integrity. Once fully cooled, the cake can be frosted or wrapped tightly and frozen.
Preparing the Irish Buttercream
- Add the softened unsalted butter to the bowl of a stand mixer (or use a hand mixer) fitted with a paddle or whisk attachment. Beat on medium-high speed for 2-3 minutes until light and fluffy.
- With the mixer on low speed, slowly add the sifted powdered sugar. Beat on low until combined, then increase to medium-high for 1 minute, scraping down the sides of the bowl as needed to achieve an even, light, and airy texture.
- Add the pinch of salt, vanilla extract, and Irish Cream liqueur (or chosen substitute). Beat on low speed until combined.
- Increase speed to high and beat until the buttercream is light and fluffy, about 3-4 minutes. Scrape down the sides once or twice during this process for the creamiest consistency.
Frosting and Storing
- Frost the completely cooled cake with the Irish buttercream. Garnish with delicate dark chocolate shavings or curls for an elegant finish.
- If not serving immediately, store the frosted cake covered in the fridge. For the best flavor and texture, bring the cake to room temperature before serving.
Nutrition
Notes
Pro Tips: Always use room temperature ingredients for proper emulsification. Thoroughly butter and cocoa-dust your pan. Allow Guinness to sit for 5 minutes to dissipate foam. Use full-fat sour cream to avoid curdling. Finely chop dark chocolate for even distribution. Beat butter thoroughly for light, fluffy buttercream. Storage & Make-Ahead: Unfrosted cake can be wrapped tightly and frozen, or stored in an airtight container at room temperature for up to 5 days. Frosted cake should be stored covered in the fridge; bring to room temperature before serving. For longer storage, freeze both frosted and unfrosted cakes, wrapped tightly in plastic wrap then foil. Nutrition information is estimated based on common ingredients and serving sizes and may vary.