The Strawberry Quark Strudel primarily requires puff pastry, strawberries, quark (or unsalted cream cheese), sugar, cornstarch, lemon juice, and an egg yolk for the egg wash. If you're looking for alternatives, you could use a different fruit like raspberries or blueberries, which would also pair beautifully with quark. For those who prefer a non-dairy option, silken tofu can be blended until smooth as a substitute for quark or cream cheese. Additionally, if you're aiming for a lower sugar variant, you can replace the sugar with a natural sweetener like honey or maple syrup, but be aware that this might alter the texture and moisture level slightly.