In a large bowl, whisk the eggs and melted butter together with a fork. Stir in the flour, baking powder and salt until dough becomes stiff. Knead on a lightly floured surface or in the bowl for a few minutes to blend completely. Divide the dough into thirds. On a lightly floured surface, roll each piece into a sheet about 1/16 of an inch thick. Place each sheet onto a dry cloth and set aside for 30 to 45 minutes to partially dry.
When the noodle sheets are somewhat dry, roll up one at a time into a loose spiral and cut into strips as wide as you want using a sharp knife. Spread out the noodles to dry for about 1 hour before cooking or storing in freezer containers. To use frozen noodles, thaw in the container before using.
To cook the noodles, drop into rapidly boiling water or broth, and cook until tender, 7 to 10 minutes.