Preheat oven to 350°. Spray an 8-inch square baking pan* with cooking spray.

In a medium saucepan, melt butter over medium heat. Add sage and garlic; cook until butter turns a medium-brown color and has a nutty aroma, 7 to 10 minutes. Remove from heat, pour into a medium or large heat-safe bowl, and let cool slightly.

Bring a pot of salted water to a boil, and cook noodles according to package directions until al dente. Drain.

To browned butter, whisk in sour cream, cottage cheese, ½ cup Parmesan cheese, eggs, parsley, salt, and pepper. Stir in cooked noodles. Pour noodle mixture into prepared baking pan, and spread evenly. Sprinkle remaining ¼ cup Parmesan cheese over noodles.

Bake until lightly golden brown and an instant-read thermometer inserted in the center registers between 165° and 175°, 30 to 35 minutes. Let cool in pan for 30 minutes.

Turn out of pan onto a cutting board. Trim and discard edges to create a 6-inch square. Cut square into 9 (2-inch) squares. Cut each 2-inch square in half diagonally to create 2 triangles. Serve warm.

Just before serving, garnish with additional sage leaves, if desired.