Crust: Lightly butter, or spray with a vegetable spray, an 8-9 inch (20-23 cm) tart pan with a removable bottom. In your food processor, place the flour, sugar, and salt and process to combine. Add the cold butter and pulse until the pastry starts to come together and form clumps. Transfer the pastry to the pan and, using your fingertips, evenly press the pastry onto the bottom and up the sides of the pan. (Can use the back of a spoon to smooth the surface of pastry). Gently pierce the bottom of the crust with the tines of a fork. (This  prevents the pastry crust from puffing up while it bakes.) Cover and place the crust in the freezer for 15 minutes to chill. (This prevents the crust from shrinking while it bakes.)

Preheat oven to 425 degrees F (220 degrees C). Place the tart pan on a larger baking sheet and bake the crust until golden brown (13 - 15 minutes). Remove from oven and place on a wire rack to cool while you make the filling.

Filling: Thaw the frozen unsweetened raspberries and then transfer to a fine mesh strainer placed over a large bowl. Gently press the berries with the back of a large spoon to release their juices. (All that should remain in the strainer is the raspberry seeds.) Put the raspberry juice, along with the sugar and jam, in a medium sized saucepan over medium heat. Stir until the jam dissolves and the sauce just comes to a boil. Reduce heat and simmer for about 10 minutes, stirring occasionally.

Meanwhile, in a small measuring cup sprinkle the unflavored gelatin over 1/4 cup (60 ml) of cold water. Let this mixture sit for about 5-10 minutes, or until it becomes softened and spongy, and then microwave about 20 seconds or until the gelatin has completely dissolved. Remove the raspberry juice from the heat and stir in the dissolved gelatin and lemon juice. Transfer to a bowl and refrigerate until the mixture starts to gel, stirring periodically (this takes about an hour).

Meanwhile, cut the strawberries into bite-sized chunks. Place the strawberries in a large bowl and fold in the thickened raspberry juice, making sure all the strawberries are coated with the sauce. Pour the strawberries into the baked and cooled pie shell and place in the refrigerator until firm (about three hours). Serve with softly whipped cream, if desired. Cover and refrigerate any leftovers. This pie can be stored in the refrigerator for a couple of days. Serves 8.

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