Sure! Prepare until the baking stage. Transfer to the baking trays, cover with plastic wrap and store in the fridge for up to 12 hours. Then just brush with egg wash and bake. Cold pastries may take a few minutes more to brown. Just keep an eye on them in the oven. Alternatively, prepare the apple filling beforehand - even a day or two in advance- then assemble and bake when you want fresh, flaky pastries.