Spinach and Cheese Gnocchi (Spinatnocken und Topfennocken)

Ingredients

• 1 ¹⁄₂ lb. stemmed spinach leaves (from about 2 large bunches), washed, drained briefly
• ³⁄₄ cup plus 1 Tbsp. butter, softened
• 1 small yellow onion, finely chopped
• 1 clove garlic, finely chopped
• 2 cups plus 2 Tbsp. ricotta, drained for 1 hour through a fine sieve
• 1 ¹⁄₂ cups plus 2 Tbsp. flour
• ³⁄₄ cup finely grated parmigiano-reggiano
• 4 eggs, lightly beaten
• 1 egg yolk
• Freshly grated nutmeg
• Salt and freshly ground black pepper
• 1 ¹⁄₂ cups fresh white bread crumbs
• 1 Tbsp. chopped flat-leaf parsley