For the apple filling:
2 1/2 pounds (about 5 whole) Granny Smith apples
2 teaspoons lemon juice
3 tablespoons unsalted butter
2 teaspoons ground cinnamon
1/4 cup sugar
1/4 cup apple cider vinegar
For the dough:
1 packet of active dry yeast (2 1/4 teaspoons)
3 1/4 cups unbleached all-purpose flour
1/3 cup sugar
1 teaspoon salt
1 teaspoon ground cinnamon
1/2 cup whole milk
2 large eggs, lightly beaten
1/3 cup unsalted butter, softened
Vegetable oil, for frying
For the glaze:
1 1/2 cups powdered sugar
3 to 4 tablespoons milk
1 teaspoon vanilla extract
Prep the apples: Core, peel, and chop apples into small pieces. Submerge them in ice-cold water with 2 teaspoons of lemon juice to prevent them from browning. Push the apples down and place a piece of parchment paper on top so the apples don't bob above the surface of the water. Set aside or refrigerate (for up to 24 hours) until ready to use.
Make the dough: Whisk together the yeast, 3 cups of the flour, sugar, salt, and cinnamon in the bowl of a stand mixer. With a dough hook and the mixer on low speed, mix in the milk, followed by the eggs. Continue mixing until the dough gathers into a ball around dough hook, 2 to 4 minutes.
Continue mixing the dough, and add in the butter one tablespoon at time. Allow each tablespoon of butter to combine into the dough before adding another. If dough starts to fall away from the dough hook, add the remaining 1/4 cup of flour 1 tablespoon at a time until dough comes back together before adding in next butter piece.
Transfer the dough to a lightly oiled bowl, turn to coat, and cover with a clean kitchen towel. Let the dough rise in a warm spot until doubled in size, 1 to 2 hours.
Make the apple filling while the dough rises: Heat the butter for the filling in a skillet over medium-high heat until butter turns brown and smells nutty. Drain the apples and add them to the pan with the butter. Sprinkle with sugar and cinnamon, and cook until tender. Add in vinegar and cook until liquid is reduced by half. Set aside to cool.
Assemble the fritters: Turn the dough out onto a floured surface. Using a rolling pin, roll the dough into a 1/2-inch-thick rectangle. Starting from the end closest to your body, scatter 3/4 of the apples over the surface of the dough, then roll it up in a long tube.
Now rotate the tube of dough so it's perpendicular to your body. Flatten the tube slightly, then scatter the remaining apples over the surface. Roll up the tube like a snail's shell — the