Preheat oven to 375°F (190°C). Set aside a 1 & 1/2- to 2-quart baking dish.
Spread the sliced apples evenly in the prepared pan.
Add the sugar, flour, lemon juice, and cinnamon, and stir to combine.
In a medium bowl, stir together the oats, brown sugar, flour, cinnamon, nutmeg, ginger, and salt. Add the butter and mix with a pastry blender, a fork, or your fingers until crumbs form. Sprinkle evenly over the apple mixture.
Bake 30 to 35 minutes, or until the top is golden brown, the filling is bubbly, and the apples are fork-tender.
Place the pan on a wire rack to let the crisp cool briefly before serving. Serve warm or at room temperature.