1.

Heat the oven to 180°C (160°C fan) and line the tin with baking paper.

2.

Put the raspberries and 1 tbsp water in a small saucepan over a medium heat. Cook until soft, mashing with a fork (5 minutes). Stir in the chia seeds and honey, then leave to thicken (10 minutes).

3.

Meanwhile, mix the flour and bicarbonate of soda in a large bowl. Rub in the butter with your fingertips until it looks like breadcrumbs (3–4 minutes).

4.

Stir in the maple syrup and vanilla, then add 2 tbsp cold water, plus up to 1 tbsp more if needed. Stir until it forms a clumpy crumble that holds together when pressed.

5.

Press two-thirds of the crumble firmly into the tin to make the base. Bake until lightly golden (10 minutes).

6.

Spread the jam over the base, scatter the remaining crumble on top, and press down gently.

7.

Bake until golden on top (20–25 minutes).

8.

Cool completely in the tin, then chill for 1 hour before cutting into 12 bars, so they hold their shape.

9.

Serve each bar with 75g Greek yoghurt.