In a mixing bowl, combine the flour, sugar, and salt for the cannoli shells. Add the melted vegan butter, plant-based milk, and apple cider vinegar. Mix until a dough forms. Knead the dough on a lightly floured surface until smooth. Wrap in plastic wrap and refrigerate for at least 30 minutes.
On a lightly floured surface, roll out the chilled dough until it's about 1/8 inch thick. Use a round cookie cutter or a glass to cut out circles, about 4-5 inches in diameter.
Wrap each dough circle around a cannoli tube, overlapping the edges slightly, and press to seal. Repeat with the remaining dough circles.
In a large pot, heat vegetable oil to a temperature of about 350°F (175°C).
Carefully place the wrapped cannoli tubes into the hot oil, a few at a time, and fry until golden brown and crispy, about 2-3 minutes per side. Use tongs to turn the cannolis to ensure even frying. Once golden brown, remove them from the oil and transfer them to a paper towel-lined plate to drain excess oil. Let them cool completely.
Once the fried cannoli shells have cooled, gently slide them off the cannoli tubes. Fill a piping bag fitted with a small round tip (or a ziplock bag with a corner snipped off) with the prepared soy ricotta filling.
Pipe the filling into both ends of each cannoli shell, filling the entire shell.
Refrigerate the filled cannolis for at least 1 hour before serving to allow the flavors to meld and the filling to set.
Serve the vegan cannolis chilled and enjoy the delightful combination of crispy cannoli shells and creamy store-bought soy ricotta filling.