Whisk together the flour, baking powder, ground nutmeg, and 1 teaspoon of sugar in a large bowl. In a separate bowl, whisk the egg with the milk until well combined. Pour the wet ingredients into the dry ingredients and stir until just combined—don't overmix, as lumps are fine and will create a tender crumb. Hull and slice the strawberries into 1/4-inch rounds and set aside. I always use King Arthur all-purpose flour because it gives these scones a consistent, delicate texture every time.
In a small saucepan over medium heat, melt the unsalted butter with the cinnamon and remaining 4 teaspoons of sugar, stirring gently until combined. Add the sliced strawberries to the warm butter mixture and stir gently to coat. Remove from heat and let the strawberries soften in the residual heat for about 1 minute. Keep this mixture warm but not hot while you cook the scones.
Heat a non-stick skillet or griddle over medium-high heat and lightly grease it with butter. Once hot, pour 2 tablespoons of batter from Step 1 onto the skillet and let it cook undisturbed for 2–3 minutes until bubbles form on the surface and the edges look set. Flip gently and cook the other side for 1–2 minutes until golden brown. Transfer to a serving plate and repeat with remaining batter. I find that keeping the pan temperature consistent prevents the bottoms from burning while the centers remain undercooked.
Layer the warm scones on serving plates by placing one scone down, dolloping with a generous spoonful of cold mascarpone, adding a few strawberry slices, then topping with another scone. Drizzle the warm cinnamon butter and strawberry compote from Step 2 over the top and around the plate. Keep the mascarpone chilled until the last moment before dolloping—this creates a beautiful contrast between the warm scones and cool, creamy cheese.