Sweet Potato Strudel with Spinach and Pine Nuts

Pastry

• 370 g plain flour, plus extra for dusting
• 40 g sunflower oil
• 120 g water, lukewarm
• 10 g vinegar
• 1 medium egg
• ½ tsp fine sea salt

Filling and Assembly

• 500 g water
• 2 ½ tsp fine sea salt, plus extra to taste
• 600 g sweet potatoes, cut in pieces (2-3 cm)
• 500 g fresh spinach leaves
• 50 g pine nuts
• ½ tsp ground black pepper, plus extra to taste
• ½ tsp ground cumin
• ½ tsp garam masala
• 100 g quark (curd cheese)
• 60 g soya milk
• 15 g olive oil, plus extra for greasing
• 2 tsp black cumin seeds