Prepare the pastry. You can use your preferred method of pre-baking a pie crust or use a packaged pie crust and follow the directions on the box for pre-baking.
Drain the thawed raspberries and reserve the syrup. Also, reserve at least 6 raspberries for garnish. If it's raspberry season, you might want to use some fresh raspberries for the garnish instead, but if it's not you can attempt to reserve some of the frozen berries for garnish. They get mushy, though!
Put the raspberry syrup in a measuring cup and add enough water to make 1 ½ cups total liquid.
In a saucpean, combine the raspberry gelatin powder and 2 tablespoons of sugar. Pour in the 1 ½ cups of rasbperry liquid and the 2 tablespoons of lemon juice. Heat over medium stirring constantly, until gelatin is dissolved. Let cool.
Combine the cooled gelatin and the drained raspberries in a bowl and chill until mixture is the consistency of corn syrup. For us, this took several hours, but I think my daughter put it in the refrigerator while still a little warm. So check the gelatin mixture periodically and don't let it get too firm.
Beat the egg whites until soft peaks start to form. Gradually add the ¼ cup of sugar and continute beating until stiff peaks form. Fold the egg whites into the slightly thickened raspberry gelatin mixture.
Next, whip the 1 cup of cream and fold it in with the egg whites and gelatin mixture. Chill the mixture until it forms mounds when spooned.
Turn the gelatin mixture into the baked crust and chill for at least 5 hours or overnight.
Garnish with raspberries. You can also garnish with sweetened whipped cream or whipped topping.