Preheat an oven to 350 degrees F. Lightly grease a 9 1/2 by 8-inch baking pan lined with parchment paper with 1 tablespoon of butter.
To make the almond topping, combine 5 tablespoons butter, 1/4 cup sugar, 1 teaspoon vanilla extract with the almonds and milk in a medium-sized saucepan. Cook over a low heat until the butter has melted, and then leave the mixture out to cool.
To make the slice, whip together the remaining 1 stick 3 tablespoons butter, 1/2 cup sugar and vanilla extract with an electric beater until pale and creamy. Sift the flour with cornstarch and add the dry ingredients to the butter mixture in 2 batches, beating on low speed until just mixed. Pour the batter into the baking pan and bake for 12 minutes, or until lightly golden brown. Remove the pastry from the oven and leave it out to cool for 10 minutes.
Carefully spread the raspberry jam over the pastry base, and then spread the cooled almond topping over the jam. Return the dessert to the oven and bake for an additional 25 minutes, or until golden.