1/2 cup thinly sliced prosciutto, cooked and crumbled
1 large egg, beaten
3 tablespoons grated Parmesan cheese
Preheat oven to 375°. Unroll crescent dough into one long rectangle; press perforations to seal. In a small bowl, beat cream cheese, green chiles and mustard. Spread over dough to within 1/2 in. of edges. Sprinkle with prosciutto. Roll up the left and right sides toward the center, jelly-roll style, until rolls meet in the middle. Cut into 1-in. slices.
Place on a parchment-lined baking sheet. Brush with egg; sprinkle with Parmesan cheese. Bake until golden brown, 12-15 minutes. If desired, top with additional grated Parmesan cheese.