Butter and flour a 10 inch springform pan.
In top of double boiler that's been set over barely simmering water, melt chocolates with butter, stirring until mixture is smooth. Remove the top of pan from heat and let mixture cool to room temperature and stir in liqueur. In large electric mixing bowl, beat egg yolks with sugar for 10 minutes,until mixture is thick and pale, and forms ribbon when beater is lifted.
In clean separate bowl and balloon whip, beat egg whites until they barely hold stiff peaks. Fold 1/3 chocolate mixture into yolk mixture, then 1/3 of the whites lightly so as not to deflate them, then fold in remaining chocolate and eggwhites in the same manner until all are just incorporated.
Turn the mixture into the prepared pan then gently drop spoonsful of remaining preserves onto batter. With fork, swirl the jam around the pan and through the batter once or twice. You don't want to fully incorporate them.
Place in pre-heated 350 degree oven for 25 to 30 minutes until the edges have puffed (the center will not be set, so don't worry about it). Let cake completely cool in pan on a rack, then set in fridge to chill for 4 hours up to 4 days.
Slice with a sharp knife you keep dipping in hot water.
Serve with a smattering of raspberries on the plate and dollops of lightly sweetened whipped cream.