"Mom's apple pie" is the gold standard of comfort-food desserts, but even classics can benefit from occasional tweaking. For example, turning your familiar full-sized pie into individual, single-serving mini-pies brings a whole new level of charm to the time-honored ingredients. Miniature tart pans are readily available, but an ordinary muffin tin works just as well and eliminates the temptation to buy single-purpose pans.
Roll your pie crust into a rectangle roughly 12 inches by 16 inches, and 1/8 to 3/16 in thickness. Cut a dozen rounds, 3 1/2 to 4 inches in diameter, with a large cookie or biscuit cutter.
Fill the cups of your muffin tin with paper or parchment muffin cups; then press a round of dough into each one. Use your fingers to shape the crust to the cup of your muffin tin, pressing it all the way into the lower corners. Press the dough with your fingers in the places where it folds and makes a double thickness so the crust spreads out to a uniform depth.
Refrigerate the pan of bottom crusts while you prepare the filling. Peel your apples and chop them into a quarter-inch dice, or, for extra-firm apples, first cut the apples into small wedges and slice the wedges crosswise into 1/8-inch triangles. Small-size pies require smaller pieces of apple in their filling.
Toss the apple pieces with diluted lemon juice to minimize browning and drain them well. Measure your usual quantities of sugar and spices to sweeten and flavor the apples; then add a tablespoon of cornstarch or quick-thickening "instant" flour to thicken the apples' juices as they cook. Whisk the sugar mixture until it's combined thoroughly; then toss the apples in it so they're thoroughly coated. Refrigerate your apples while you roll the dough for your top crusts.
Preheat your oven to 425 degrees Fahrenheit. While it's heating, roll out the remaining dough and cut a dozen circles with a 2 1/2- to 2 3/4-inch diameter, re-rolling the scraps if necessary. Remove your filled pan of bottom crusts from the fridge and load each cup generously with apples. The filling should rise above the crust, because it will shrink as it bakes.
Moisten the edges of each crust with water or beaten egg. Slash the top crusts to vent steam; then place one crust over each mini-pie and press to seal it firmly to the bottom crust. Bake for 20 to 25 minutes, until the crust is golden and the apples are soft. If your apples are still firm at that point, reduce the oven to 325 F and continue baking them until they're tender.
Remove your pies from the oven when they're done, and let them cool in the pan for 10 to 15 minutes before removing them. If you'd like to remove the paper cups, do it while the pies are still slightly warm. Filling tends to bubble out and stick the pies to their paper cups, and if you wait for them to cool completely, it'll be much harder to remove them.