Preheat the Oven: Set your oven to 220°C (425°F). Line a baking sheet with parchment paper.

Mix the Dry Ingredients: In a large mixing bowl, stir together the self-raising flour, sugar, and salt.

Incorporate the Butter: Add the cold butter to the bowl. Use your fingertips to rub the butter into the flour until the mixture looks like coarse breadcrumbs.

Add the Wet Ingredients: Pour in the milk and heavy cream. Stir gently with a spatula until the dough starts to come together. If using raisins or currants, fold them in now.

Shape the Dough: Sprinkle a light layer of flour on your work surface, then place the dough on it. Gently press it into a 1-inch thick circle or square. Avoid overworking the dough.

Cut the Scones: Use a round cutter (or knife for wedges) to cut out scones. Place them on the prepared baking sheet.

Brush with Cream: Lightly brush the tops of the scones with extra heavy cream for a golden finish.

Bake the Scones: Bake for 12-15 minutes, or until the tops turn a golden brown color.Remove from the oven and let them cool slightly.

Serve and Enjoy: Serve warm with clotted cream and jam for an authentic British tea experience.