Preheat oven to 350 degrees. With a chopper or small food processor, finely chop the almonds.

In a small bowl, combine the flour, brown sugar, butter, and almonds. Spread the crumbled mixture on a baking sheet lined with foil or parchment paper, and bake for 18-20 minutes, stirring occasionally, until golden brown; cool on a wire rack.

Sprinkle 2/3 of the almond mixture evenly over the bottom of the 9×13 inch dish. Set aside the remaining 1/3 cup for the topping.

In a large bowl, whip the egg whites with the lemon juice until they can hold a soft peak. Gradually add white sugar while continuing to whip to firm peaks. Fold in the raspberries.

In a separate bowl, whip the cream with an electric mixer until stiff; add vanilla when thick. Fold into the raspberry mixture. Mix together and spoon over the crust in the dish and spread evenly.

Top with the remaining almond mixture. Freeze for 6 hours, or overnight.