In a large bowl, combine the sliced apples, 0.75 cup sugar, 2 tablespoons flour, cinnamon, nutmeg, and lemon juice. Toss to coat the apples evenly. Pour the apple mixture into a 9x13 inch baking dish.
In a separate medium bowl, whisk together 1.5 cups flour, 0.75 cup sugar, baking powder, and salt.
Cut in the cold butter using a pastry blender or your fingertips until the mixture resembles coarse crumbs.
Pour in the milk and stir until just combined. The dough will be thick and shaggy.
Drop spoonfuls of the topping mixture over the apple filling, covering as much of the surface as possible.
Bake for 35-45 minutes, or until the topping is golden brown and the apple filling is bubbly.
Let cool slightly before serving. Serve warm, perhaps with a scoop of vanilla ice cream or a dollop of whipped cream.
Notes
For best results, use a mix of apple varieties for a complex flavor. Granny Smith, Honeycrisp, and Fuji are excellent choices.