Cut meat into strips. Rinse the lemon with hot water and pat dry. Grate 1 teaspoon of zest, halve the lemon and squeeze out the juice. Mix 2 tablespoons of juice with paprika powder and drizzle over the meat, leave to steep for 10 minutes. Finely grate half of the Parmesan and grate the rest. Chop garlic finely. For the dressing, put sunflower oil, mustard, egg yolk, grated Parmesan, garlic and anchovies in a tall container and mix with the hand blender. Stir in the yogurt and season with 2 tablespoons of lemon juice, salt and pepper.
Heat grill pan. Cut the ciabatta into slices. Rub the pan with olive oil (1 tbsp). Roast the slices until crispy on both sides, about 5 minutes. Remove, let cool, dice. Rinse the salads, drain them, cut them in half and grill them in the pan with the cut side down for 2-3 minutes. Rinse and clean the spring onions and cut them diagonally into fine rings. Mix the meat with 1 tablespoon of oil and fry on all sides in a non-stick pan (it should be pink on the inside). Fry the onions briefly at the end. Serve meat with salad, dressing, croutons, lemon zest, spring onions and shaved Parmesan.