Smoked Salmon Roll-Up

Ingredients

• 2 teaspoons poppy seeds
• 1/4 teaspoon garlic powder, or more to taste
• 1/4 teaspoon onion powder, or more to taste
• 1/2 cup (68 grams) all-purpose flour
• 1/4 cup (32 grams) cornstarch, plus more for dusting
• 6 large eggs, separated, at room temperature
• 1/2 teaspoon fine sea salt
• Finely grated zest and juice of 1⁄2 lemon
• 8 ounces (226 grams; generous 1 cup) whipped cream cheese
• 4 ounces (113 grams) smoked salmon, finely chopped
• 2 scallions, trimmed and thinly sliced
• 2 tablespoons finely chopped fresh dill, or to taste
• 2 tablespoons snipped fresh chives, or to taste
• 2 teaspoons capers, rinsed, patted dry and chopped
• Freshly squeezed lemon juice, to taste
• Fine sea salt and freshly ground black pepper
• Finely sliced cucumber (peeled or not), for finishing (optional)
• Finely sliced radishes, for finishing (optional)
• 1 handful arugula, if serving the cukes and radishes as a salad