Heat the oven to 170C fan,190C for convection or gas mark 5.
Grease an 18 cm square pan (or 23 cm square pan for a shallower bake) and line with baking parchment or silicone liner.
Place the prepared apples in a pan with 2 tablespoons of water. Bring to the boil and simmer until tender and pulpy.
Add the dates, 50g of the brown sugar, and date syrup. Simmer for a further 5 minutes. Take off the heat and using a wooden spoon, break the apples and dates down until the ingredients are combined together. Set aside to cool.
Gently melt the butter in a pan, or, if preferred, place the butter in a microwaveable bowl and heat for 1 minute (cover the bowl to prevent the butter from spitting).
Add the flour, bicarbonate of soda, oats, sesame seeds and remaining 200g of soft brown sugar to a bowl and combine well.
Pour the melted butter into the oat mixture and mix until the oats are well coated. Add the vanilla extract and mix again.
Transfer half your oat mixture to your pan. Press it firmly into the bottom of the pan and spread the apple mixture evenly over the top of the oats.
Now cover the apples with the remaining oat mixture and press down firmly, ensuring all the apple layer is covered and sealed.
Place in the oven and bake for 30-35 minutes or until golden brown and firm. Whilst still warm, brush the top with a little apricot jam.
Allow to cool in the pan. Once cold, tip the bake onto a board and cut into 16 pieces.
Store in an airtight container. They will keep for a week.