Ingredients for the base

1. Preheat the oven to 180℃ fan, and line a 8 x 8 inch square / loose base tin with grease proof paper.  Allow the paper to hang over the edges of the tin, this makes it easier for removing the bars when ready.
2. Sift the flour and sugar into a medium sized mixing bowl and add in the oats. 
3. Add in the cold butter and zest of 1 lemon. Using your fingertips, rub into the flour mixture crumbly dough forms.
4. Crumble the dough into the base of the tin and press down with your hands or a off set spatula. Tip: Dust your fingers with flour, it prevents the dough from sticking.
5. Set aside while you make the lemon filling.

Method (lemon filling)

1. Place all of the lemon filling ingredients into a medium sized  saucepan over medium heat. Stir constantly until the mixture thickens (this will take around 5 minutes). Stirring will prevent any sticking and burning, and will remove any lumps. 
2. Once the mixture is thick and glossy, remove it from the heat. Spread the lemon filling over the base and smooth it out with the back of a spoon or off-set spatula. Do this immediately while the lemon mixture is still warm as it will become thicker as it cools.
3. Make the cheesecake layer.

Method (lemon cream layer)

1. Wash, then drain the cashew nuts and place them into a high speed blender along with the cream cheese, silken tofu, sugar and lemon zest. Blend on high speed until smooth. You may need to stop the mixer and use a spatula to scrape down the sides to ensure everything is incorporated. 
2. Carefully pour the smooth cheesecake mixture on top of the lemon curd, use a off-set spatula to spread it out even.

Method (Crumble)

1. In a bowl, sift the flour, oats and sugar. Stir to combine.
2. Add in the butter, using your fingertips, rub the butter into the dry mixture. You don’t want to form it into a ball but break it up into a crumble. 
3. Sprinkle this over the dessert in an even layer.
4. Bake in the middle of the pre-heated oven until golden in colour for approximately 40-50 minutes, it may need longer depending on how thick your layers are. If the crumble looks like it’s burning at any point, cover with some grease proof paper and continue baking. To check the dessert is ready to come out the oven, insert a skewer down the middle, it should jiggle slightly but will firm up when cooling.
5. Remove from the oven and allow the bar to cool in the tin. I prefer to leave it in the tin on the worktop to cool fully, then cover with grease proof paper and place in the fridge overnight.
6. Once ready, life out of the tin and place on a board.
7. Use a sharp knife to cut the bars into slices. Allow to room to room temperature so that the butter can soften slightly before enjoying.  
8. Serve and enjoy!