Preheat the oven to 425°F / 220°C with a baking sheet inside.
Mix 350g of self-rising flour, 1 teaspoon of baking powder, and ¼ teaspoon of salt. Rub in 85g of cubed butter, then add 3 tablespoons of sugar.
Warm 175ml of milk until warm but not hot. Stir in 1 teaspoon of vanilla extract and 1 squeeze of lemon juice.
Mix the milk into the flour with a table knife, just until it forms a dough.
Lightly dust the counter with flour. Fold the dough twice, pat to 1½in / 4cm thick and cut with a 2in / 5cm round cutter. Press the scraps together and repeat.
Brush with 1 beaten egg. Place on the hot sheet and bake for 10-12 minutes, until risen and golden.
