Defrost phyllo and lay out the phyllo sheets to dry completely. This can take hours to overnight.
Lay them all on the counter so they dry evenly. Once dry, crumble up all the sheets and place in a large bowl.
In another bowl, mix together eggs, sugar and citrus juice (the original recipe called or oranges but I used lemons instead) until a smooth cream forms. Then gently stir in the dried crumbled phyllo so all the pieces are coated evenly.
Cut 2-25inch pieces of foil and fold so you get 2 long rectangle pieces. Lay the foil in the slow cooker, making a criss-cross. This will help you pull the pie out of the slow cooker easily. Then place a long piece of parchment paper in the slow cooker, tucking the foil so it holds the parchment paper down.
Pour the mixture in the slow cooker and cook on low for 3 hours. Once done, the edges should be slightly crisp and tender in the middle.
While the slow cooker phyllo pie is cooking, make the simple syrup by combining water, sugar and lemon zest in a small pot. Bring to a simmer and let cook for 10 minutes. Then add the lemon juice, stir to combine and let cool to room temperature.
Once the phyllo pie is done, pour the syrup all over the hot pie and let the layers soak up the sweet syrup.
Once pie is cooled, remove from the slow cooker by lifting with the foil handles. Then cut phyllo pie into squares and serve.