(With credit to Riri Clark, "Ari", and "Nora")
1 lb. unsalted butter, softened
3 large eggs
1/2 tsp salt
3/4 cup edam cheese, finely shredded
1/2 cup sharp cheddar cheese, finely shredded
2 3/4 cups all-purpose flour
Note: This recipe makes about 60 little biscuits.
Preheat the oven to 350F. Mix the cheeses together gently with a fork. In a large bowl, beat the butter with an electric mixer on medium until it is very smooth and creamy. Separate two of the eggs, setting the whites aside. Add the salt and the two egg yolks to the butter and mix well.
Add the cheese and flour to the mix 1/3 at a time, alternating between cheese and flour. When it's all mixed together, transfer the dough to a lightly floured surface and knead until the dough is soft and smooth. Roll out to about 1/4 inch thickness and cut in to 1 inch squares.
To form the biscuits, take one of the squares and pinch it from the sides to make a little finger-shape (about 2 inches long and 1/2 inch wide), transferring to an ungreased cookie sheet as you go. Leave about an inch between biscuits.
Mix the two egg whites from earlier with the third egg and brush on the tops of the biscuits. Bake at 350F for about 30 minutes. The kastengel will turn a very light brown color. If you disturb them before they cool off, they practically disintegrate, so let them sit for 15 minutes or so before removing from the baking sheet.
Here's the finished product: