Mashed Potatoes and Savoy Cabbage - Lidia

Ingredients

• 1 pound Savoy cabbage, cleaned, cored, and coarsely chopped
• 1 pound Idaho potatoes, peeled and sliced 1 1/2 inches thick
• Kosher salt
• 1 bunch scallions, white and tender green parts, trimmed, cleaned, and sliced thin (about 1 cup)
• 1/2 cup whole milk
• 4 tablespoons unsalted butter
• 1 apple
• 1 teaspoon grated lemon zest
• Freshly ground black pepper