Preheat the oven and prepare the tin. Set your oven to 190°C (170°C fan). Line a 12-hole muffin tin with paper cases or grease the holes thoroughly with butter or oil. The batter will be quite thick, so paper cases help the muffins dome nicely.

Mix the dry ingredients. In a large bowl, whisk together the plain flour, granulated sugar, baking powder, bicarbonate of soda, and salt. The mixture should look uniform and pale, with no lumps of bicarbonate of soda visible. Whisking aerates the flour, giving you lighter muffins.

Add the wet ingredients. Make a well in the centre of the dry ingredients. Pour in the orange zest, orange juice, milk, vegetable oil, eggs, and vanilla extract. Stir gently with a wooden spoon or spatula until just combined. You will see streaks of flour still — that is exactly right. The batter should look thick and shaggy, not smooth like cake batter.

Fold in the cranberries. Tip the cranberries into the batter. Fold them in with just four or five strokes. You want the berries evenly distributed, but you must stop as soon as the last streak of flour disappears. The batter will be lumpy and thick, and you should see a few cranberries peeking through the surface.

Fill the muffin tin. Using a large ice cream scoop or two spoons, divide the batter evenly among the 12 muffin holes. Each hole should be almost full — the batter will be mounded slightly above the rim. This ensures tall, bakery-style domes. If using, sprinkle a pinch of demerara sugar over each muffin for a crunchy top.

Bake until golden and springy. Place the tin in the centre of the oven and bake for 16 to 18 minutes. At 16 minutes, check them: the tops should be a deep golden brown, and the edges should look set. The muffins should feel springy when you gently press the centre with your fingertip, and a skewer inserted into the middle should come out clean or with a few moist crumbs (not wet batter). The kitchen will smell beautifully of toasted orange and sweet berries.

Cool briefly, then enjoy. Let the muffins rest in the tin for 5 minutes — this allows the structure to set. Then transfer them to a wire rack to cool completely if you’re not serving them immediately. If you’re eating them straight away, wait just 2 minutes after the rest, then serve warm. The cranberries will be soft and bursting with juice.