Preheat oven to 350°F (175°C).

Bring 4 quarts of water to a boil in a large pot.

Lightly boil spaetzle for 10-12 minutes, then drain and reserve.

In a medium frying pan, saute chopped bacon until crisp.

Remove bacon with a slotted spoon and drain on paper towels. Reserve.

Add diced onion, apple, salt, and pepper to the pan drippings.

Saute onion and apple mixture for 4-5 minutes until softened.

Add sliced bratwurst to the pan and cook for an additional 5-8 minutes, or until heated through.

Lower heat and add cream cheese and the reserved bacon to the pan.

Continue stirring until the cream cheese is blended and smooth.

Remove from heat and stir in sauerkraut, Swiss cheese, and cooked spaetzle.

Coat a 9 x 12 inch baking pan with cooking spray.

Add the mixture to the prepared pan.

Top with pats of unsalted butter.

Bake covered for 15 minutes, or until the cheese is bubbly and melted.