3 tart apples (530 grams whole) such as Granny Smith, peeled and finely diced
2 tablespoons maple syrup
1 1/2 teaspoons ground cinnamon
1/8 teaspoon salt
For the glaze:
1 1/2 cups icing sugar
3 to 4 tablespoons half-and-half
1 teaspoon vanilla extract
1/8 teaspoon ground cinnamon
4 to 5 cups canola oil, for frying
For the dough, mix the warm water and sugar in a large bowl (or the bowl of a stand mixer). Sprinkle in the yeast, stir gently, and let sit five minutes.
In a separate bowl, mix the flour, baking powder, cinnamon, and salt. Once the yeast is foamy, stir in the buttermilk, butter, and egg. Mix in the flour, one cup (150 grams) at a time, with a wooden spoon or dough hook if using a stand mixer. Mix thoroughly, adding extra flour a bit at a time if the dough is too sticky. Knead (by hand or with the mixer) until you have a soft, smooth, and gently elastic dough. Place in a greased bowl, cover with a damp tea towel, and let rise until doubled in size, about 45 minutes.
While the dough is rising, prepare the apple filling. Melt the three tablespoons (43 grams) of butter in a large frying pan over medium-low heat, then add the apples, maple syrup, cinnamon, and salt. Stir frequently for 10 to 15 minutes, or until the apples have softened. Remove from the heat and let cool.
Once the dough has risen, press it down, then turn it out onto a floured surface. Sprinkling with flour to prevent it from sticking, roll out the dough into a 23 × 33 centimeter rectangle. With the longer edges of the rectangle at the top and bottom, spread two- thirds of the apple filling on one side of the rectangle. Fold the other half of the dough over it and seal the edges. Turn the dough so the longer sides are on the top and bottom again. Spread the remaining one-third of the apple mixture on one side, fold the dough over, and seal once again. Now you have a layered square of dough filled with chunks of apple. Sprinkle a generous amount of flour over a baking sheet and set aside. Using a knife or bench cutter, cut the dough so you have about 48 small squares. Gather four squares at a time and press them together to form one fritter. Don’t worry if they look a bit rough or the apples have to be pressed back in—you want a crater-like surface for these. Once all the fritters are formed, place them on the prepared baking sheet, cover very loosely with plastic wrap, and let rise.
While the fritters are rising, fill a large pot with about ten centimeters of oil and heat to 360°F (182°C). In a bowl, whisk together the icing sugar, half-and-half, vanilla, and cinnamon for the glaze.
Lay out a baking sheet and place a cooling rack on top of it. When the oil is hot, gently drop the fritters in one or two at a time, depending on the size of the pot (they shouldn’t crowd each other). Fry until golden brown on one side, then flip over and fry until golden brown on the other, three to four minutes in total. Remove with a slotted spoon and place on the cooling racks.
Once the fritters have cooled enough to handle, dip one side into the glaze, shake off the excess, and place it back on the rack, glazed side up. The glaze shouldn’t coat the fritters too thickly; once you start dipping the warm doughnuts into it, you’ll know if you need to add more cream to thin it out. Repeat until all the fritters are fried and glazed.