For the chicken filling:
Place the chicken quarters, the carrot, celery and 1 whole onion into a medium pot. Cover with cold water and season the water with 1 teaspoon of salt. Place the pot over high heat and bring it to a boil. Reduce the heat to medium low and cook on a simmer for about 2 hours until the both is golden and the chicken is fork tender and cooked.

Meanwhile,  place a small pan over medium low heat. Place 2 tablespoons of oil into the pan.  Add the finely chopped onion into the pan and ½ teaspoon of salt. Saute the onions for about 30 minutes. Reduce the heat to low and cook for another 30 minutes. Turn off heat and set aside. 

Remove the chicken from the soup. Strain the broth and the vegetables (use for another dish).

Remove the skin  and bones from the chicken and then shred the chicken with a fork. Discard the skin and bones.

Place the shredded chicken, sautéed onions, ½ teaspoon of salt and pepper into a food processor or meat grinder. 

Pulse the mixture a few times, about 7 to 10 times until it is finely chopped into a chunky mixture  but not a smooth puree. Set aside.

For the cheese filling:
Place the raisins into a large heat-proof bowl. Cover with boiling hot water and allow the raisins to steep for about 10-20 minutes, or until they are plump and hydrated.

Once the raisins are steeped, drain from water. Discard the water. 

Place the raisins, farmers cheese or ricotta cheese, sugar and vanilla into a large bowl.

Mix to combine. Set aside.

For the naleskini:
Warming the milk and water (if using whole milk or almond milk) in a small saucepan over medium heat until the milk is lukewarm.

Meanwhile, measure the flour by spooning the flour into a measuring cup until it is level. This will give you a more accurate cup. Add the flour, salt, and sugar into a large bowl.

Once the milk is lukewarm, slowly begin to stream it into the flour, salt and sugar mixture. As you are adding the milk to the flour, you want to be whisking it vigorously. After all of the milk (and water if using) is incorporated, add the egg and oil into the mixture. Continue to whisk for 2-3 minutes until well combined. 

Let the mixture sit on the counter for 10 minutes.

Whisk the mixture again for 2-3 more minutes, or until it is smooth with no lumps.

Your batter should appear very watery, this is normal. It is a very thin and airy batter, which is critical to making thin nalesniki. If your batter seems viscous or thick, add more milk, almond milk or water, 1 teaspoon at a time until it is at the right consistency.

Once the batter is ready, heat a 10-inch nonstick skillet on the stove. The pan must be nonstick.

Place the pan over medium-high heat  and once the pan is hot, add slightly less than ⅓  cup of batter to the pan. Immediately raise the pan and flick your arm around, allowing the batter to pour all over the pan and seep to fill the surface. Your batter should be thin enough that it moves quickly across the pan without issue. This process is similar to making crepes. 

Cook nalesnik for about 1 minute on the first side, then flip with a spatula, tongs or your hands and cook for another 45 seconds on the second side until just golden. Place the cooked nalesniki on a tray.  You want them to remain soft and pliable, not crispy.

Repeat this process with the remaining  batter. Set the nalesniki aside.

For the assembly and serving: 
Open the nalesniki on a large plate and put 2 heaping tablespoons of the desired filling about 2 inches from to top end of the nalesniki, shaping it into a 3 inch by 1 inch log. Fold the lower edge of the nalesniki over the filling, then fold the side inwards and continue to roll the nalesniki, until it is sealed. Repeat with the remaining nalesniki and filling. 

To serve, you will want to crisp the filled nalesniki on a pan with about 1 teaspoon of oil. Place the oil into a non-stick pan over medium heat. Place the filled nalesniki into the pan and cook for about 2 to 3 minutes per side until golden brown and crisp. 

Serve the nalesniki at room temperature or warm. Serve the chicken nalesniki plain or with fried onions on top, and the cheese nalesniki with sour cream, strawberry jam and dusted with confectioners sugar.