Heat the oven to 220C/fan 200C/gas 7 and fill a large saucepan with water. Bring the pan to the boil, then lower the heat to gently simmering and stir in the bicarb, malt and Marmite (careful – it will bubble up!). Use a floured finger to push a hole down through the centre of each dough ball, then lift from the paper. Swirl it gently around your finger to stretch the hole a little, but don’t knock out too much air, then lower carefully into the poaching pan. Do 2 bagels at a time if your pan allows, and poach for 2 minutes, turning over halfway. Using a slotted spoon, lift out the bagels and return to the paper-lined baking trays. Repeat to poach all the bagels, keeping the water at a gentle simmer.