Milk that has turned goes into pancakes, not down the sink

It happens in every kitchen. I open the fridge for the morning tea, pour a splash of milk, and it tastes slightly sharp. Not bad, just tangy, the way kefir is tangy. The bottle is still within its date, it was opened only a few days ago, and it has been in the fridge the whole time. For years I would have poured it away. Now that milk goes into a bowl of thick, soft pancakes, and the sharpness is exactly what makes them rise.

First, the honest part, because not every sour milk is the same. Milk from the shop is pasteurised, and when pasteurised milk goes off, it is spoiling, not turning into something like old-fashioned sour milk. So I am careful. I only use milk that is still within its use-by date, has been kept cold, and is just slightly tangy. If it smells bad rather than sour, if it is lumpy, bitter, or thick like yoghurt, or if it is past its use-by date, it goes down the sink and I don't think twice. Food safety advice is clear that the use-by date is the one that matters for milk, and I follow it.

Most mornings, I don't even wait for the milk to turn. I make my own tangy milk on purpose: 250 ml of fresh milk with one tablespoon of lemon juice or white vinegar, stirred and left for ten minutes until it thickens slightly. A glass of kefir works the same way. The acid reacts with the bicarbonate of soda, and that is what makes the pancakes light and full of little holes. Plain milk and soda alone would give flat, heavy pancakes.

The batter takes five minutes. In a large bowl, I whisk one egg with a tablespoon of sugar and a pinch of salt, then pour in the tangy milk. I sift in 180 g of plain flour with half a teaspoon of bicarbonate of soda and a teaspoon of baking powder, and stir with a spoon just until there is no dry flour left. A few lumps are fine. If I beat it smooth, the pancakes come out tough. Last, two tablespoons of melted butter or sunflower oil. The batter should be thick, so that it drops slowly from the spoon. Then I leave it alone for five minutes while the pan heats. In that time, small bubbles appear on the surface, and I know they will rise.

I cook them on a medium-low heat in a heavy pan, lightly oiled with a piece of kitchen paper. A tablespoon of batter for each pancake, three or four at once, with room between them. I don't touch them until the top is covered in bubbles and the edges look dry, about two minutes. Then I turn them once, and give the second side about a minute. They puff up in front of you. If the outside browns too fast and the inside is still raw, the heat is too high. The first pancake is always the test one, and in our house, it is the cook's.

A stack of them goes onto a warm plate under a clean tea towel while I finish the rest. We eat them with honey, soured cream and a few berries, or with a spoon of jam. In autumn, I grate half an apple into the batter and add a pinch of cinnamon, and the kitchen smells of baking for the whole morning. Leftover pancakes keep in the fridge, covered, for a day or two, and I warm them in a dry pan until they are hot right through.

The pancakes contain milk, egg and wheat. With a little plant milk and lemon juice, they still work, though they are a bit less tender.

If you like a thinner pancake, my American-style pancakes are a good next step, and the kefir drop scones use the same tangy-milk idea. Do you use slightly sour milk for baking, or does it always go down the sink?

Tangy-milk pancakes. Makes about 16 small pancakes. About 25 minutes. You need 250 ml milk (within its use-by date, slightly sour, or fresh milk with 1 tbsp lemon juice), 1 egg, 1 tbsp sugar, a pinch of salt, 180 g plain flour, ½ tsp bicarbonate of soda, 1 tsp baking powder, 2 tbsp melted butter or oil. Whisk the egg, sugar, salt and milk; stir in the sifted flour, soda and baking powder; add the butter. Rest 5 minutes. Cook spoonfuls on a medium-low heat for about 2 minutes, turn, and cook 1 minute more, until risen and cooked through.