Preheat the oven to 350°F and lightly grease a 9-inch tart pan (or pie plate) if needed.
Unroll the pie crust and press it into the prepared pan, trimming any excess and creating a neat edge. Prick the bottom all over with a fork.
Blind bake the crust for 10 to 12 minutes, or until lightly golden. Remove it from the oven and let it cool slightly.
Spread the raspberry jam evenly over the warm crust.
In a medium saucepan over low heat, melt the butter, corn syrup, and granulated sugar, stirring until the sugar dissolves and the mixture is smooth.
Remove the saucepan from the heat, add the corn flakes, and gently fold until all the flakes are evenly coated.
Spoon the coated corn flakes over the jam layer, pressing down lightly to compact the topping.
Bake for 10 to 15 minutes, or until the topping is golden brown and caramelized, watching carefully to avoid burning.
Allow the tart to cool in the pan for 15 to 20 minutes, until the topping is set, before slicing.
Serve warm with hot custard, vanilla ice cream, or on its own with a cup of tea or coffee.