Preheat your oven to 400 degrees F and line a baking sheet with parchment paper. Place the sheet in the refrigerator to keep it cold while you prepare the dough.

In a large bowl, whisk together the flour, baking powder, salt, sugar, and cinnamon. Add the cold butter cubes and use a pastry cutter or your fingertips to cut the butter into the flour until the mixture looks like coarse, uneven crumbs with some pea-sized pieces still visible. If you grate frozen butter on the large holes of a box grater, toss it into the flour immediately and work quickly so it stays cold.

Add the shredded cheddar and the diced apple to the flour mixture and toss gently with a fork to distribute them evenly. In a small bowl or measuring cup, whisk together the cold heavy cream and the egg. Pour the liquid over the flour mixture and stir with a fork just until the dough starts to come together. Stop as soon as no dry patches remain. The dough will look shaggy, and that is exactly right.

Lightly flour your work surface and turn the dough out onto it. Gently press and fold the dough 3 to 4 times until it holds together, then pat it into a circle about 7 to 8 inches across and 1 inch thick. Do not roll it with a rolling pin. Use a sharp knife or bench scraper to cut the circle into 8 equal wedges, like a pizza.

Transfer the wedges to the chilled parchment-lined baking sheet, spacing them about 1 inch apart. Brush the tops lightly with the remaining tablespoon of heavy cream. Bake for 18 to 22 minutes, until the tops are deep golden brown and the edges look set and dry. The cheese on top will be lightly browned and a little crispy in spots.

Let the scones cool on the pan for 5 minutes before serving. They are at their absolute best warm, when the cheese is still slightly stretchy and the apple pieces are soft and fragrant.