Prepare filling first by stirring together sugar and cinnamon. Set aside.
Divide pie dough into two pieces (if you don't already have it divided in two). Place one back in the refrigerator to keep cool and roll out the second into a long rectangle that’s just over 7” wide and just over 21” long. Cut into 6”-7” squares until you have three squares, then repeat with second half of pie dough until you have six pie squares total. Set aside
Place peeled, cored apple in the center of pie dough square.
Pour about 1 ½ Tablespoon of filling into the center of apple. Top with a small piece of butter.
Fold one corner of the pie dough square over the top of your apple. Then take the opposite corner and overlap the first, moisten your finger with water and lightly dampen the pastry to encourage it to stick together. Repeat with opposite corners (see photos in post or video below for visual).
Carefully transfer apple to 9x13 baking dish (I use two 9x13 dishes for this recipe to avoid over-crowding the pan). Repeat until all apples have been filled and covered in pastry.
Prepare syrup by combining 1 cup granulated sugar, 2 cups water, 3 Tablespoons butter, and ¼ teaspoon ground cinnamon in a medium-sized saucepan. Stir well and place over medium heat. Bring to a boil, stirring occasionally. Once boiling, remove from heat and set aside.
Give syrup another stir and then carefully pour around apples in each pan (do not pour on top of dumplings).
Transfer apple dumplings to 425F (215C) oven and bake 40-45² minutes or until apples are tender (I’ll usually poke them with a wooden skewer to test).
Before serving, top with a bit of the syrup from the pan.
¹I recommend a firm, tart apple. I like Gala or Honeycrisp, Granny Smith would also work. My grandmother likes to use Red Delicious.²If you are using particularly small apples they will need to bake for less time, and of course large apples will need to bake for longerI got this recipe from my grandmother, who actually took it from Betty Crocker's Picture Book!