Lightly butter a 1.2-litre pudding basin. Mix the rhubarb, sugar and 2 tsp water in a small heatproof bowl. Cover with cling film and microwave on High for 1-1½ mins, until the rhubarb is just beginning to soften. (Alternatively, cook for 5 mins in a small saucepan, until the sugar has dissolved and the rhubarb softens slightly.) Drain rhubarb, reserving the juices, then mix the rhubarb with 4 tbsp of the strawberry conserve. Spoon into the pudding basin.
Put all of the sponge ingredients in a large bowl, then beat with an electric whisk for 1 min until light and creamy. Spoon into the basin, taking care not to dislodge the rhubarb, then smooth the top.
Lay a large sheet of greaseproof on top of a piece of foil the same size. Butter the paper, pleat in the middle and cover the pudding. Tie tightly with string under rim of basin, then trim, scrunching foil up around the paper to make it watertight. Place the pudding in a large saucepan on an upturned saucer. Pour justboiled water to halfway up the basin, cover, then steam for 1½ hrs. Check the water level every 30 mins or so and top up if you need to. To test when the pudding is ready, unwrap and insert a skewer into the sponge. It should come out clean with no trace of raw mixture.
Just before serving, heat reserved rhubarb juices with the remaining conserve in a small saucepan or in the microwave until bubbling. Turn out the pud, drizzle the hot sauce over the top and enjoy with custard. To make ahead, leave the pud in its basin to cool, then recover and chill. Steam for 20 mins, or invert
onto a heatproof plate and microwave on High for 5-10 mins to warm through.
To make individual puddings: Heat the oven to 180C/fan 160C/gas 4 and boil the kettle. Divide the rhubarb
topping between 6 lightly greased 200ml dariole moulds, then top with the sponge mixture. Smooth over the surface and loosely cover each pudding with some buttered foil, scrunching around the sides to give the sponge room to rise. Place the puddings in a deep roasting tray and pour in boiling water from the kettle until halfway up the sides of the moulds. Bake for 25-35 mins until the sponge has risen and an inserted skewer comes out clean. Serve with the extra rhubarb and strawberry syrup.