For the date filling
For the oat mixture
Heat the oven to 200°C, gas mark 6.
Line a 20cm square baking tin with baking paper, leaving some hanging over the sides.
In a small saucepan, combine the dates, water and zest over a low heat, simmering for 5-10 minutes, until the mixture has thickened. Set aside.
In a large bowl, mix the oil, oats, flour, spices, bicarbonate of soda and salt and stir to combine.
Press half the mixture into the bottom of the prepared tin.
Spread the date mixture over the base and sprinkle the remaining oat mixture on top. Press down lightly.
Bake in the preheated oven for 25-30 minutes or until golden brown. Allow to cool then cut into squares.
Store in an airtight container for up to 3 weeks.