Mix the cold coffee and the liqueur in a large bowl. In batches, dip the ladyfingers in the coffee mixture. You want them to be moist on the outside but still crunchy on the inside.
Beat the egg yolks with half of the sugar until the mixture is thick enough to form a long ribbon when you lift the beater out. (If you are concerned about using raw eggs, once you have beaten the egg yolks, cook them in a double boiler, whisking constantly until they become as thick as a custard cream. Be careful not to overcook them, or they will become scrambled eggs. After cooking the yolks, proceed with the recipe.)
Add the mascarpone and beat for 2 to 3 more minutes. Set aside.
Beat the egg whites, adding the remaining sugar a bit at a time, until they form stiff peaks and have a glossy sheen, about 4 minutes.
Gently fold the egg whites into the mascarpone mixture until the mixture is all the same color. Add the vanilla and chopped semisweet chocolate, and gently fold them into the mixture.
In a 9-by-17-inch glass baking dish, assemble the dessert. Layer the bottom of the dish with the soaked cookies. Top with a layer of the mascarpone-chocolate mixture. Repeat the procedure to make 1 more layer.
Using a flour sifter, cover the top of the tiramisù with a thin layer of sweet cocoa powder.
Place the tiramisù in the refrigerator and let it rest for at least 5 hours; it’s even better if refrigerated overnight.
Serve it with pride!
You may notice that there’s enough of the mixture left over to make an additional, smaller tiramisù. This usually doesn’t happen to me, because I keep tasting to make sure that there is enough sugar and chocolate. By the time I am done, there is enough for only one pan. Don’t laugh - it might happen to you, too.
Place the frozen strawberries in a food processor. Add the cassis and sugar. Pulse until pureed. Taste.
If the texture of the strawberry seeds bothers you, strain through a fine-mesh strainer or cheesecloth-like strainer to remove the seeds; otherwise, it is ready to serve.