Step 1: Preheat and Prep
Let’s dive in—crank your oven to 350°F and feel the kitchen hum with promise. Grab two 8-inch wide x 3-inch deep cake pans—grease them generously with butter or spray, then line the bottoms with parchment rounds (I love that extra slip!). Take a sec to breathe—this is gonna be a fudgy wonder, and you’re already rocking it.

Step 2: Whisk the Dry Mix
In a big mixing bowl, whisk 1 3/4 cups all-purpose flour, 2 cups granulated sugar, 3/4 cup unsweetened cocoa powder, 2 teaspoons baking soda, 1/2 teaspoon baking powder, and 1 teaspoon fine salt—give it a good stir (I love that cocoa cloud poofing up!). It’s all dry and ready—set it aside and feel the chocolate vibes starting. This is the base of our boozy dream!

Step 3: Blend the Wet Magic
In a medium bowl, whisk 3/4 cup sour cream (or yogurt), 1/2 cup vegetable oil, 3 large eggs, 1 teaspoon vanilla extract, and 1 cup Guinness beer—mix until it’s smooth and that stouty fizz blends in (I grin every time I see those bubbles!). Keep going ‘til it’s a happy, velvety swirl—my heart’s racing with that beer twist. This is where the moistness comes alive!

Step 4: Combine and Pour
Pour your wet mix into the dry, stirring gently with a spatula until just combined—watch for flour pockets but don’t overmix (I love seeing it turn into batter!). Divide it evenly between your two pans—smooth the tops and pop them in the oven for 35-40 minutes—check with a cake tester ‘til it’s clean, then cool in the pans for 30 minutes before turning onto racks (I’m drooling just thinking about it!). If you can, freeze the cakes while you whip up the buttercream—it’s my secret for easy frosting.

Step 5: Whip the Irish Buttercream
In a big bowl, beat 4 sticks of cool unsalted butter with a mixer ‘til light and fluffy—take your time (I love that creamy swirl!). Gradually add 6 cups sifted powdered sugar, then 1/4 cup plus 2 tablespoons Irish cream—beat on high for 3 minutes ‘til it’s silky and smooth (I sneak a taste of that Bailey’s kick!). Adjust with more cream if thick or sugar if thin—it’s frosting heaven now!

Step 6: Assemble the Layers
Place one cake layer on a stand or plate—spread a big scoop of buttercream over it, smoothing with an offset spatula (I pile it on for that naked look!). Stack the second layer, flat side up—spread a thin crumb coat all over, sealing in those crumbs like spackle (I feel like an artist here!). Chill it in the fridge or freezer ‘til firm—then frost with the rest, focusing on the top for that rustic vibe—I’m grinning at this beauty!

Step 7: Make the Chocolate Drip
Chop 4 ounces semisweet chocolate and toss it in a heatproof bowl—heat 1/2 cup heavy cream in a small pan ‘til simmering, then pour over the chocolate (I love that steamy moment!). Cover for a few minutes, then stir ‘til smooth—let it cool 10 minutes ‘til thick but pourable (I test it on a glass—too thick, zap it; too thin, wait!). This ganache is gonna drip like a dream.

Step 8: Add the Drip and Decorate
Pour some ganache over the chilled cake—smooth it quick with an offset spatula to the edges, then use a squeeze bottle to drip down the sides (I go slow and feel fancy!). Before it sets, sprinkle on chocolate curls or sprinkles—don’t wait too long or they won’t stick (I love that final flourish!). Let it set a bit—room temp is perfect for that fudgy bite.