The night before: Spread a thin layer of strawberry jam on one slice of bread, top with a layer of sliced strawberries and over with another slice. Set aside. On low-medium heat, in a medium saucepan, combine brown sugar, butter and corn syrup. Stir often, until mixture comes together and begins to thicken. Immediately pour into a Pam-sprayed 9x13 pan and spread with a wooden spoon to ensure even coverage. Sprinkle with crushed walnuts evenly and set sandwiches on top, side by side, filling 9x13 pan (6 sandwiches). In a separate bowl, beat eggs, add milk and vanilla, mixing well after each addition. Pour egg mixture over top of the sandwiches, making sure no dry spots are left (pay particular attention to corners). It may look like too much egg mixture, but it will soak in. Cover with plastic wrap and store in refrigerator over night.
In morning: Preheat oven to 350 degrees F. Put 9x13 pan with sandwiches in oven, baking for approximately 45 minutes, or until tops of bread are toasted but not burned. Remove 9x13 pan from oven, and cut outline of sandwiches with a knife so they are easy to remove. Immediately invert each onto its own plate with a large spatula, so that the caramel is on top. This must be done rather quickly, as the caramel will stick to the 9x13 pan as it cools. Garnish with whipped cream and half a strawberry.