Stir together 1/4 cup sugar and cinnamon and set aside.
Whisk together flour, salt, and remaining 2 teaspoons sugar in a large bowl. Add milk in a slow stream, whisking, then add eggs, 1 at a time, whisking well after each addition.
Peel apples, then cut into 1/8-inch thick slices with slicer, rotating around core (discard core). Cut apple slices into 1/8-inch-thick matchsticks and toss with lemon juice in a bowl. Fold apples and juice into batter.
Heat 1 piece butter (1/2 tablespoon) in a 6-inch nonstick skillet over moderate heat until foam subsides, then add 1/3 cup batter, spreading evenly to cover bottom. Cook, reducing heat if browning too quickly and turning pancake over once with a thin flexible heatproof spatula, until golden on both sides, about 4 minutes total. Slide pancake onto a platter and keep warm in oven. Make more pancakes with remaining butter and batter in same manner. Sprinkle with cinnamon sugar and serve immediately.
Batter, with apples, can be made 3 hours ahead and kept chilled, covered. Stir before using.