Add flour to the bowl of a stand mixer and form a well. Add the egg yolks, water and olive oil. Slowly knead using a dough hook until the dough comes together.
Then knead by hand until smooth and elastic. Add a tablespoon of water if needed (the texture should be smooth and elastic but not crumbly or sticky).
Cover with plastic wrap and let rise for 30 minutes in the refrigerator. Use the amount needed for a recipe.
Mix the mozzarella with the Espelette and chives. Season with salt and set aside.
Divide the ravioli dough in two balls.
On a floured workspace, roll out dough into thin sheets using a rolling pin.
Wet one of the sheets with water using a pastry brush.Make tiny mounds of mozzarella then cover with the second sheet of dough.
Lightly press around the cheese filling with your fingers to seal. Cut out raviolis using a pastry cutter.
Bring a large pot of salted water to a boil.
Cook the raviolis for 2 to 3 minutes. Strain then mix with the pesto.
Serve with basil and toasted pine nuts. You can also accompany the raviolis with a tomato basil sauce or a creamy chive sauce.