1. Freeze the Baci, unwrap and chop coarsely, approximately the size of a cherry pit. Return to freezer until ready to use.
2. In a small bowl, stir the crumbled amaretti and brandy together until blended; add the frozen chopped Baci and return to the freezer until ready to use.
3. In the top of a double boiler or in a medium-sized heat-proof bowl, whisk the egg yolks, 1/2 of the superfine sugar and the wine together until smooth. Place over barely simmering water and continue beating (you can switch to a hand held electric mixer at medium speed if you like); until the mixture is pale yellow; fluffy and falls back on itself in thick ribbons when the whisk or beaters are lifted, about 8 minutes if beating by hand, 4 if using an electric mixer. It is important to whisk continuously, or the egg yolks will cook and the mixture will appear curdled. Remove the top of the double boiler or the bowl from the heat and set it in a large bowl of ice water. Whisk constantly until cold.
4. In a large bowl, whip the heavy cream with an electric mixer at medium speed until it holds stiff peaks when the beaters are lifted. Clean the beaters well and dry them.
5. In a medium-size bowl, beat the egg whites with the electric mixer at medium speed until foamy. While continuing to beat, gradually add the remaining 1/2 cup sugar and beat until the whites are glossy and hold stiff peaks when the beaters are lifted.
6. Add about one fourth of the beaten egg whites to the chilled Marsala mixture and, with a rubber spatula, gently fold them in, scraping the Marsala mixture from the bottom of the bowl over the whites. Fold in the remaining whites in the same way. Fold the Marsala mixture into the whipped cream in the same way.
7. Line a 9x 5 x 3 inch loaf pan snugly with plastic wrap. Sprinkle the bottom with an even layer of the Baci mixture, 1/3 of the mixture. Spoon one third of the egg mixture over that; tap the bottom of the pan on a hard surface to settle the mixture in an even layer over the egg-cream mixture. Repeat the sequence, finishing with the last third of the egg-cream mixture. Smooth the surface with a spatula, cover securely with plastic wrap and freeze until solid, at least 8 hours or up to 2 days. (Semifreddo, if tightly wrapped, will keep for up to 1 week in the freezer.)
To Serve: Remove the top layer of plastic wrap and invert the pan onto a platter large enough to hold the semifreddo. Tap the bottom of the pan sharply to loosen the frozen mixture. Remove the pan and the plastic wrap and, with a long thin knife, slice the semifreddo into 3/4 inch thick slices.
NOTE: Although only an extremely small percentage of eggs contain salmonella bacteria - which, if the eggs are improperly handled, can multiply and cause salmonellosis - it is worth noting that desserts and other dishes that call for uncooked eggs or eggs that are cooked below a temperature of 160 degrees F can possibly cause illness. to greatly reduce this risk, buy only very fresh eggs in uncracked shells, refrigerate them immediately, and use them as quickly as possible. Wash your hands and all work surfaces and utensils thoroughly before and after working with eggs. It is best to avoid these dishes altogether if you will be serving children, elderly people, or those with compromised immune systems, or if you live in an area that has experienced outbreaks of salmonellosis.