Illinois Pierogi

Cheese Filling

• 17 ½ oz water
• 16 oz potatoes, peeled, cubed (1 in.)
• 4 oz yellow onion, quartered
• 3 tbsp unsalted butter
• 1 ½ tsp semolina
  or 1 ½ tsp all-purpose flour
• 13 oz mascarpone cheese
• ¾ tsp salt, to taste
• ¾ tsp ground black pepper, to taste

Dough

• 9 oz warm water, plus extra to seal and boil pierogi
• 1 large egg
• 1 oz grapeseed oil
• 17 ½ oz all-purpose flour, plus extra to dust
• 2 pinches salt, to taste, plus extra to boil water (approx. 3 tbsp per 4 qt)

Topping

• 16 oz yellow onions, quartered
• 2 oz unsalted butter, cubed, plus extra to fry
• 2 oz extra virgin olive oil
• fresh parsley leaves, to garnish (optional)