Pre-heat oven to 190°C / 170°C fan assisted / gas mark 5 / 375°F. Line and grease a 23 x 30cm (9 x 12 inch) cake tin, with the baking parchment pressed up and over each side. Leave the edges of the baking parchment hanging over the sides and secured in place with mini bulldog clips.
In a medium sized bowl stir the cream cheese, jam and egg together until well combined then set aside.
Place the sweet rice flour, oat flour, tapioca flour, rolled oats, sugar, baking powder and salt into a large mixing bowl and rub together with your fingertips until the mixture resembles rough breadcrumbs.
Stir in the hazelnuts.
Tip half the mixture into the cake tin and press in tightly and evenly.
Spread the cheesecake mixture over the top of the tin, then tip over the rest of the oat mixture, pressing down as firmly as you can without disrupting the cheesecake layer.
Place in the oven and bake for 40 minutes.
Remove and leave to cool completely in the tin. Remove from and cut into squares.