Combine all of the pastry ingredients either in a stand mixer with paddle attachment or in a bowl and mix by hand. Bring everything together into a smooth dough, but it should not be sticky. Knead for a few minutes (around 3-5  in mixer or 5 - 8 by hand) then cover with plastic wrap and set aside at a cool room temperature to rest. Leave for around 30 - 45 minutes.

While the dough is resting, also drain the ricotta in a fine strainer set over a bowl, or a slightly less fine strainer lined with kitchen paper. Towards the end, you can squeeze a little to help remove excess liquid.

Combine the drained ricotta, sugar, lemon zest and cinnamon in a bowl and mix well. Add some of the egg yolk, or all if needed, and mix through. It will become a little more runny, so you may not want all of it as it can be too liquid, but the egg helps the texture as it cooks. Fold in the chocolate chips to distribute relatively evenly.

Place the filling in the fridge or simply set aside as you roll out the dough. Start with half of the dough and leave the rest covered. Roll it out as thinly as you can - it should look around the thickness of a lasagna sheet, if possible, as it will likely spring back and become a little thicker as you fill and seal it.

Use a large round cutter, around 4in/10cm diameter, and cut out circles from the dough - try to cut them close together to minimize scraps needing to be re-rolled. Remove the scraps and ease the circles of dough from the work surface.

Place a teaspoon of the filling in the middle of each circle of dough. Drain off any excess liquid from the filling as you scoop it before placing on the dough.

Lightly brush the edge of the dough with the reserved egg white then fold one side over the other to form a half moon shape. If your dough has been shrinking, it can be good to stretch it back out a little as you fold over. Use the tips of a fork to press the edges together tightly and seal in the filling. You may want to lift the ravioli from the work surface then repeat sealing it with the fork to make sure they are well-sealed.

Repeat forming the ravioli with the rest of the dough and filling (you can join the scraps of dough and re-roll but take care they are well-joined together). Meanwhile, warm a pan with a good depth of oil to fry the ravioli. You want the oil to be deep enough that the ravioli will be covered.

Once the oil is hot (around 350F), fry in batches of two or three at a time so that the oil doesn't cool too much. Turn over, as needed, during cooking until both sides are golden brown. Remove from the oil with a slotted strainer and drain on kitchen paper, then repeat with the rest of the ravioli. Dust with powdered sugar before serving, ideally while still warm.