Potato Cheddar Perogies

I have been having dreams about these homemade perogies that one of the ladies who I used to go to the gym with made.  They were the best perogies I have ever eaten.  When I saw this Potato Cheddar Perogie recipe here I had to try to make them.  They were really yummy, but I must admit a lot of work.  However with my current string of failures it was nice to have a night of success all of the kids ate these).

Potatoe Cheddar Perogies
Ingredients
Filling
3 cups peeled and diced Yukon Gold potatoes
1/3 cup unsalted butter
coarse salt and ground black pepper
1 dash ground nutmeg
1 cup finely grated Cheddar cheese (optional)
Dough
5 cups all purpose flour
2 teaspoons fine salt
4 large eggs
1 cup 2 % milk
3/4 cup water
For serving
1/4 cup unsalted butter
3/4 cup finely diced onion
coarse salt and ground black pepper
5 slices cooked bacon

Directions
Filling
For filling, cook potatoes in boiling salted water until tender, and drain. Mash by hand. Season to taste and add nutmeg. If adding cheese, allow potatoes to cool, then stir in grated cheese. Chill potato filling before using.
Dough
For dough, combine flour and salt. In a separate bowl, whisk eggs, milk and water. Add liquid to flour and stir until blended. The dough should be soft enough that it sticks to the bottom of the bowl, but not so soft that it doesn’t hold its shape. Cover dough and let rest at room temperature for 1 hour, or chill dough until ready to use then pull out of fridge an hour before rolling.
On a lightly floured surface, roll out dough as thinly as possible without tearing. Use a round cutter 3 inches (8 cm) in diameter and cut out circles of dough. Place 1 Tbsp (15 mL) of potato filling into the center of each perogy and pinch the perogy edges closed. Perogies can be frozen on a baking sheet or kept chilled until ready to cook.
For serving
To serve, melt butter in a sauté pan over medium-high heat. Add onions, stirring constantly until onions are richly browned. Reduce heat to medium-low. In a pot of boiling salted water, cook about half of the perogies until they float, about 5 minutes.
Remove from water with a slotted spoon; add to browned butter and cook remaining perogies. Stir in bacon.  then transfer to a bowl to serve.