Pre-heat the oven to 180°C/350°F/gas mark 4.

Lay a 50cm wide piece of foil on a work surface. Place a 30cm piece of baking parchment on top of the foil and grease it lightly with oil. Set this aside.

In a bowl, mix together the flour, caster sugar, cardamom (optional), salt and vegetable suet.

Add the milk and mix to form a shaggy dough.

Knead gently for 2-3 minutes until the dough is soft and slightly elastic.

Spread the jam all over the surface of the dough, leaving a 1cm gap at the edges to prevent overspill.

With the longest edge closest to you, begin to roll the dough into a log, like how you'd roll up a cinnamon bun.

Carefully lift the roll and place it on the greased baking parchment, near the edge. Roll the log in the baking parchment/foil loosely. If it's too tight, it won't have enough space to expand.

Fill a large roasting tin with boiling water and place an oven-safe baking rack on top. Place the wrapped Roly Poly on top of the rack. Bake for 35 minutes. Remove from the oven and allow to cool for 10 minutes. Increase the oven temperature to 200°C/400°F.

Stir together the agave and dairy-free milk. Unwrap the Roly Poly and brush the with the milk mixture. Sprinkle with Demerara sugar. Return the Roly Poly to the oven for 5 minutes until golden all over. Allow to cool for 10 minutes.

Cut the Vegan Jam Roly Poly into thick slices and serve with custard.