Thoroughly scrub potatoes with vegetable brush and water. Cut in half and add to a large pot. Add enough water so that potatoes are fully submerged. Cover pan and bring to a boil. Reduce heat to medium so that a soft boil will continue until potatoes are soft (about 40 minutes). To test softness, poke a fork; they should be soft all the way through. Place potatoes in a strainer and cool.
Preheat oven to 375 F. Peel potatoes (discard skin) and place in a medium bowl. Mash by hand until smooth. Measure out 2 cups. Add salt, olive oil, eggs, and cheeses. Set aside (or store in refrigerator in sealed container for up to 2 days).
In a large mixing bowl, mix together flour and salt. Push flour to the side to create a crater in the middle and add canola and water. Thoroughly mix until moist. Knead gently to combine into a dough consistency.
Prepare flat area for rolling borecas. Roll a small amount of dough into a ball (the size of a strawberry) and roll out with a rolling pin, smooth glass or your fingers. Make sure that the dough is thin, otherwise it will get too thick in the oven.
Scoop a small amount of filling into the middle of each dough circle. Fold over into a half-moon shape.
Pinch edges together and press fork on the edge to decorate and ensure full closure.
Place on a baking sheet lined with parchment paper or is lightly oiled. Lightly brush each boreca with extra beaten egg. Sprinkle with grated parmesan cheese. Bake for 20 to 25 minutes or until golden brown around the edges.
Sometimes, I'll make a bunch of filling and then keep making the dough, one batch at a time, until I run out of filling.
Preparation and baking time: 1-1/2 hours
Serves: 8 to 10
Recipe adapted by Julie Negrin from Sephardic Cooking, Sephardic Biker Holim Ladies Auxiliary of Seattle © 1960s (exact year unknown)