In a 10-in. cast-iron or other ovenproof skillet, melt 3 tablespoons butter over medium heat. Add pears; cook and stir until tender, about 5 minutes. Stir in 1/4 cup brown sugar and lemon juice.
In a bowl, whisk the flour, milk, eggs, syrup, vanilla and salt until smooth; pour over pears. Bake at 450° until puffy, 10-12 minutes.
Meanwhile, in a microwave-safe bowl, melt remaining butter in a microwave. Stir in cinnamon, nutmeg and the remaining brown sugar. Spread over pancake. Bake until golden brown, 8-10 minutes. Cut into wedges and serve immediately. If desired, top with whipped cream.