Preheat the oven to 190°C, fan 170°C, gas 5. In a heatproof jug, combine the dried mushrooms, 300ml boiling water, and let aside for 20 minutes.
Drain, reserving the liquid.
In a large saucepan, heat 2 tablespoons of oil. 4 tbsp. water, shallots, Portobello mushrooms, carrots, and swede Cook until the shallots are softened, about 10 minutes.
Cook for 1 minute after adding the corn flour. Add the stock, conserved porcini liquid, and wine gradually.
Cook for 3-4 minutes, stirring constantly, until the liquid has thickened.
Combine the lentils, porcini mushrooms, chopped thyme, and redcurrant jelly in a mixing bowl.
Season well, then transfer to a large oven-proof dish or casserole pot.
Cut the potatoes into rounds using a sharp knife. Cook for 5-6 minutes, or until the potatoes are somewhat softened.
Drain the potatoes and put them in rings on top of the hotpot, slightly overlapping them.
Apply the remaining oil on the brush. Cover the potatoes with foil and bake for 50 minutes, or until they are barely soft.
Raise the oven temperature to 220°C (gas 7) and 200°C (fan). Remove the foil and continue baking for another 30 minutes, or until the potatoes are golden brown.
