Mum's Impossible Pie

This is the British wartime trick that makes a single bowl of batter behave like a three-layer dish. Eggs, milk, melted margarine, flour, baking powder, and salt whisk into a thin batter that, when poured over a filling and baked, splits as it sets: a tender crust on the bottom, a soft custard in the middle, and the filling suspended through it. No pastry rolling, no blind baking, no fuss.

The South London origin is what gives it the name. Working-class home cooks during rationing pulled together meals from whatever the cupboard offered, and this batter bent to whatever they had: a tin of tuna or salmon, an onion, frozen mixed veg, and evaporated milk for the savoury version; sugar, desiccated coconut, an extra egg, and vanilla for the sweet.

Both versions go into the same lightly greased pie plate and bake until set. The batter is the constant. Only the filling changes, depending on whether you’re feeding the family supper or pudding.

This is a recipe to memorize. Once you have the batter ratio in your head, you can throw an impossible pie together with whatever is in the fridge.

Pro Tips

• For the savoury version, drain the canned tuna or salmon thoroughly. Excess liquid waters down the custard and ruins the set.
• For the sweet version, use unsweetened desiccated coconut. Sweetened versions push the sugar level too high and brown unevenly.
• Whisk the eggs and milk thoroughly before adding the flour. Lumps in the batter give you visible gluey patches in the finished pie.
• Don’t overcrowd the filling. Two cups maximum for either version. More than that and the batter can’t bind properly.

Variations

• Try a savoury version with cooked bacon, grated cheese, and chives instead of fish.
• Make a sweet version with apple slices, cinnamon, and brown sugar instead of coconut.
• Stir 1 tablespoon of curry powder into the savoury batter for a kedgeree-inspired hybrid.