Let the dough sheets rest at room temperature for about 15 minutes. Roast the pine nuts in a pan and let them cool down. Clean and wash the chard. Cut leaves and stems finely. Peel, wash and finely dice potatoes. Blanch potatoes and chard in boiling salted water for about 3 minutes. Drain, rinse and drain.
For the filling, grate the parmesan finely. Peel garlic and chop finely. Coarsely chop the olives. Wash the rosemary and chop the needles coarsely. Mix cream cheese with parmesan, garlic, olives, rosemary and approx. 2⁄3 pine nuts. Season with salt and pepper. Mix with potatoes and chard.
Melt the butter. Remove 6 pastry sheets from the package (use the rest for other purposes). Wrap 3 dough sheets in a damp tea towel until ready to use. Place 3 dough sheets on a damp tea towel, spreading each layer thinly with butter. Spread half of the filling on top, leaving about 1.5 cm of edge all around. Whisk the egg with cream and brush the edges of the pastry with it. Fold the sides of the dough slightly over the filling, then roll it up tightly with the help of the cloth. Carefully place in a greased casserole dish (approx. 18 x 26 cm). Work the rest of the dough and filling into another strudel.
Spread the strudel with the rest of the egg and sprinkle with sea salt. In a preheated oven (electric cooker: 200 °C/circulating air: 180 °C/gas: see manufacturer) for approx. 50 minutes
For the dip, mix quark, sour cream, mayonnaise and curry until smooth. Season to taste with salt. Serve the strudel sprinkled with the rest of the pine nuts. Serve with dip.