Cut rhubarb stalks into 1 inch pieces and place onto a suitable oven proof dish. Sprinkle over 30g of sugar and place into a preheated oven for 10-15 minutes at 180C until the rhubarb is softened but still has form.
In the meantime, mix together oats and ground almonds in a large bowl and set aside.
Melt butter, sugar, and honey in a pan or microwave. Do not allow it to burn. Add vanilla extract then pour over the oat mixture. Stir thoroughly to combine.
Using 3/4 of the oat mixture, press firmly onto the bottom of a 20x20cm lined baking tray. Set aside.
Once the rhubarb is cooked. Spoon over the oat mixture. Add blackberries. Then spoon over remaining oat mixture. Level gently with the back of a spoon.
Place into the oven and bake for 20-30 minutes until the top has become golden and the sides have begun to pull away from the side of the tray.
Cool before removing from tray. Serve warm or cold.
Will keep well in an airtight container for a few days or in the fridge.
