Preheat the oven to 200°C and line a 12-hole muffin tin with paper cases.
Melt the butter in a pan over low heat and cool for a few minutes.
Sift the flour and bicarbonate of soda into a bowl, then stir in sugar, blueberries, and lemon zest.
Whisk the eggs until smooth, then incorporate yogurt, milk, and melted butter.
Lightly mix the wet ingredients into the flour mixture.
Divide the batter between the cases and top each with a teaspoon of lemon curd and sugar.
Bake for 20 minutes until risen and golden-brown.
Allow to cool on a wire rack before serving.