Cocktail knishes with spinach and smoked salmon

Ingredients:

Filling

• 450 g peeled potatoes for baking
• 1/4 cup vegetable oil
• 1 large Spanish onion, chopped (2 cups)
• 0.5 cups blanched and coarsely chopped spinach

Dough

• 3/4 cup vegetable oil
• 3/4 cup water
• 2.5 cups premium flour
• 1/4 tsp ground cumin
• 1/4 teaspoon turmeric
• 0.5 tsp salt
• 110 g smoked salmon, chopped
• A quarter bunch of flat-leaf parsley, washed

Preparation:

1. Filling:
   
   Place the potatoes in a saucepan, cover with water, and cook until tender when pierced with a fork (20 minutes). Drain. Meanwhile, sauté the onion in oil until soft. Mash the potatoes and add the fried onion and spinach.
2. Prepare the dough:
   
   In the bowl of a stand mixer fitted with a paddle attachment, combine the butter, water, cumin, turmeric, salt, and 1.5 cups of flour. Add more flour or water, if necessary, to form a soft dough. Form into two balls. Wrap in plastic wrap and let rest at room temperature for 30 minutes.
3. Assembly:
   
   Roll out the dough into two 0.3 cm thick rectangles (approximately 37 x 25 cm). Place the filling in the center in a square. Arrange the fish in an even layer on top of the filling. Trim the dough and roll it up. Refrigerate for 20 minutes.
4. Preheat the oven to 190°C. Cut the knyshes into 5 cm (2 in) pieces. Place them seam-side down on a non-stick baking sheet or a parchment-lined baking sheet. Bake for 30 minutes, until golden brown. Sprinkle with parsley.