Start by brewing your espresso. Use your preferred method. I often opt for a stovetop espresso maker. The key is to make it strong, as it needs to soak through the ladyfingers effectively. Set it aside to cool down to room temperature.

In a mixing bowl, combine the egg yolks and granulated sugar. Use a hand mixer or a whisk to beat until the mixture becomes pale and creamy. This step usually takes about 5 minutes of vigorous mixing.

Gently fold the mascarpone cheese into your egg mixture. Pour in the Irish cream liqueur and coffee liqueur, and mix until smooth. Take care to maintain that light, airy texture.

In another bowl, whip the heavy cream until stiff peaks form. If using an electric mixer, keep an eye on it; we don’t want butter, just perfectly whipped cream!

Now, gently fold the whipped cream into the mascarpone mixture. Use a spatula for a lighter touch. You're looking for a homogeneous but still airy blend.

Grab your ladyfingers and quickly dip them into the cooled espresso, coating them briefly. Too long in the coffee, and they'll become mushy. Layer them in a dish, covering the bottom, followed by half of the cream mixture.

Repeat this process. Place another layer of dipped ladyfingers on top of the cream mixture, followed by the remaining cream. Smooth the top to make it just right.

Cover the tiramisu with plastic wrap and refrigerate for at least 4 hours, or ideally overnight. This step is crucial. It allows the flavors to meld beautifully.

Before serving, dust with cocoa powder and sprinkle the finely chopped bittersweet chocolate on top. For a little zing, consider adding the orange zest just before serving for extra flair.