Make crust: Break shortbread into pieces and pulse pieces with nuts in a food processor until finely ground.
Press firmly over bottom and 1 1/4 inches up side of a 24-centimeter springform pan. Bake crust in middle of oven 10 minutes, then cool in pan on a rack.
Make filling: Beat eggs, 1/2 cup sugar, and a pinch of salt in a metal bowl with a handheld electric mixer at medium-high speed until doubled in volume, about 5 minutes. Set bowl over a saucepan with 1 inch of simmering water and beat custard until an instant-read thermometer registers 140°F, about 5 minutes. Continue beating over heat 3 minutes more. Remove bowl from heat and chill custard until cool, about 10 minutes.
Toss raspberries with remaining tablespoon sugar in a large fine sieve set over a bowl, then force berries through sieve, pressing on solids, and discard seeds. Fold strained raspberries into cooled custard.
Beat cream with cleaned beaters until it just holds stiff peaks and fold gently into raspberry mixture.
Spoon filling into crust, smoothing top. Wrap pan in foil and freeze at least 4 hours. (Filling will be firm but not frozen solid.)
Run a thin knife around edge of torte and remove side of pan.