Bring a small saucepan filled 3/4 full with water to a gentle boil. Place the two whole eggs into water, making sure they are fully immersed.
Cook for 15 minutes, drain, and cool immediately in ice water for ten minutes. When cooled, remove shells and refrigirate for 5 minutes before slicing into 1/4 inch slices.
Bring a medium-sized saucepan filled 3/4 full with water and 1 tsp salt to a gentle boil.
Place the cleaned and sliced potatoes in the water. Cook for 10-12 minutes or until barely tender. Remove from heat, gently place potatoes in a strainer, and drain.
Preheat oven to 350 degrees. Lightly spray a casserole dish.
In a 1-cup liquid measuring cup, combine the egg yolk, salt, pepper, and sour cream. Set aside.
Arrange 1/3 of the potatoes on the bottom of the baking dish. Arrange the sliced sausage in an even layer on top of the potatoes.
Add 2 Tbsp of the sour cream mixture to the top of the sausage and smooth it out evenly.
Arrange 1/3 of the potatoes and add the egg slices. Add 2 Tbsp of the sour cream mixture and smooth it out evenly.
Add the remaining potatoes and top with the remaining sour cream mixture.
Add lid or cover the dish with foil and bake for 30 minutes. Remove lid and increase the temperature to 400 degrees. Cook for 10 minutes or until the top is golden.
Remove from oven and let sit for 15 minutes before slicing.