Step 1Toast oatmeal by spreading in thin layer on baking sheet and baking at 350 degrees about 10 minutes. Set aside.
Step 2Beat egg whites and dash salt with electric mixer until very stiff and dry, then gradually beat in sugar, a little at a time. Add cornstarch and vinegar, continuing to beat.
Step 3Process oatmeal, dried fruit and nuts together in food processor to medium-fine grind. Fold into egg-white mixture.
Step 4Spoon mixture into (9-inch) springform pan that has been lined with lightly greased wax paper. Spread smooth and bake at 350 degrees in lower part of oven until light brown and crisp on the top, 30 to 40 minutes. Remove from oven and cool.
Step 5Gently remove cake from pan and place on serving dish. Dust cake with powdered sugar. Whip cream; fold raspberries into whipped cream.
Step 6To serve, offer dollop of raspberries and cream with each slice.