Step 1: Prep the Oven and Pan
Set a rack in the center of your oven and preheat to 350°F. Butter your 9-inch springform pan generously—sides and bottom—then line it with parchment paper. This double insurance keeps your Irish Apple Cake from sticking, and the springform makes it easy to pop out later.

Step 2: Mix the Dry Ingredients
In a medium bowl, whisk together the granulated sugar, baking powder, cinnamon, salt, ginger, nutmeg, allspice, and 3 cups of flour. Add the cold butter cubes and use your hands to work it in—pinch and rub until it looks like wet sand with no big chunks left. It’s a bit messy, but that’s where the texture magic happens.

Step 3: Combine Wet and Dry
In another medium bowl, whisk the eggs, heavy cream, and vanilla until smooth. Pour this into the dry mix and stir with your rubber spatula until it just comes together—don’t overmix, or the cake gets tough. You want a thick, luscious batter that’s ready for the apples.

Step 4: Add the Apples
In a small bowl, toss the apple slices with the remaining 3 tablespoons of flour until coated—this keeps them from sinking. Fold them gently into the batter, then scrape everything into the prepared pan. Smooth the top, then sprinkle the demerara sugar over it for that golden crunch.

Step 5: Bake It Up
Bake for about 1 hour and 20 minutes, until the apples are tender and a toothpick in the center comes out clean. The kitchen will smell like a spiced Irish orchard—pure heaven. Let it cool completely in the pan so it sets up nicely.

Step 6: Make the Custard Sauce
In a heatproof bowl, whisk the egg yolks and sugar for about 6 minutes until pale and creamy. In a heavy saucepan over medium-low heat, scrape the vanilla bean seeds into the cream, add the pod, and heat until just boiling—watch it closely. Whisk a few tablespoons of the hot cream into the yolks to temper them, then slowly add the rest, whisking constantly. Return it to the pot and cook over medium-low, stirring until thickened—test it with a spoon; your finger should leave a clear streak. Strain through a fine-mesh sieve, discard the pod (add extract here if using), and let it cool.

Step 7: Serve and Enjoy
Slice the cooled Irish Apple Cake and drizzle with custard sauce. Each bite is a mix of tender cake, tart apples, and creamy richness—a true taste of Ireland.