Heat the oven to 375°F and grease a baking sheet. Combine the flour, oats, brown sugar, baking powder, salt, nutmeg, and 1 teaspoon of the cinnamon in a large bowl. Add 7 tablespoons of the butter and blend with a pastry cutter or your fingers until the mixture resembles coarse crumbs. Add the cream and vanilla and stir just until combined, then transfer the dough to a floured surface and knead 5 or 6 times.
Transfer the dough to the baking sheet, and roll or press it into an 8-inch circle. Melt the remaining 1 tablespoon butter in a small saucepan over medium-low heat (or in a microwave-safe bowl in the microwave). Brush the dough with it. Combine the remaining ¼ teaspoon cinnamon with the sugar and sprinkle it over the dough. Cut the dough into 8 equal wedges and separate them just enough that they no longer touch.
Bake the scones until golden brown, 25 to 30 minutes. Serve warm or at room temperature.
