1 Small pot, 1 Baking sheet, 2 Bowls, 1 Measuring cups, 1 Small knife, 1 Tablespoon, 1 Teaspoon, 1 Fine-mesh sieve, 1 Brush, 1 Rolling pin, 1 Hand mixer, 1 Kitchen towel, 1 Piping bag, 1 Plastic wrap, 1 Parchment paper
1 In a bowl, beat together flour, 2 tablespoons oil, 1 pinch of salt and 200 ml (approximately 2/3 cup) lukewarm water with dough hook of a hand mixer until smooth, about 5 minutes.
2 Shape the dough into a ball, coat with the remaining oil and wrap tightly in plastic wrap. Let rest in the refrigerator for 2 hours.
3 Rinse lemon in hot water, wipe dry and finely grate half of zest. In another bowl, beat together 60 grams (approximately 1/4 cup) butter, sugar and 1 teaspoon lemon zest until fluffy. Drain quark in a fine sieve.
4 Combine eggs, whipping cream, sour cream and drained quark in a bowl and mix into the butter mixture.
5 Place dough on a large flour-dusted kitchen towel (about 70 x 70 cm) (approximately 27 x 27 inches). Roll out dough into a rectangle with a floured rolling pin.
6 Dust hands with flour and gently stretch the dough to about 60 x 60 cm (approximately 24 x 24 inches).
7 Melt remaining butter and spread about half of lukewarm butter onto 2/3 of the strudel dough; set remaining butter aside.
8 Sprinkle breadcrumbs over the dough, then spread the quark mixture on the lower half of the dough.
9 Fill a piping bag with plum jam and pipe onto the quark mixture.
10 Roll the dough into a tight log, using the towel to help lift the dough as you work. Place log on a parchment-lined baking sheet.
11 Brush log with some of the reserved butter and bake in preheated oven at 200°C (fan 180°C, gas: mark 3) (approximately 400°F) for about 45 minutes, brushing with milk after about 10 minutes. Let cool slightly, then sprinkle with powdered sugar and serve.