Heat oven to 425.Place butter in 12-inch ovenproof skillet and set in oven to melt the butter. Skillet should be hot when you pour in the batter.In medium mixing bowl, combine flour, milk, eggs, nutmeg, and salt. Whisk until blended but don't over mix.Pour batter into hot skillet.Bake 15-20 minutes, until pancake is puffy and deep golden brown.Remove skillet from oven.Immediately squeeze lemon over pancake and then sprinkle with powdered sugar.Serve immediately with your favorite jam or preserves.