While this is a great breakfast dish, we usually have it for dinner. It's a hearty meal that can be sized up or down easily. The very first time I made it, back in 1981 as a new bride, I misread the directions and used 2 CUPS of milk! I figured it out after waiting forever for it to set. We eat this with ketchup, but you can try salsa, too.
Cook potatoes in their skins in boiling water in a large saucepan until barely tender, about 15 minutes.Drain; return to pot; shake over very low heat to dry.Peel and cut into 1/4" slices. (Slices should be firm, but not overcooked.
Cook the bacon in a large skillet until crisp. Drain on paper towels; crumble; reserve.
Pour off bacon fat from skillet into a measuring cup. Measure and return 4 tablespoons to the skillet. Add onion; sauté 5 minutes or until tender.
Add potato slices; cook for 10 minutes, turning to brown evenly. Add more bacon fat if necessary.
Beat eggs in a bowl until creamy; beat in milk, salt, pepper, and chives.
Sprinkle the reserved bacon over the potatoes. Pour in the egg mixture to cover evenly.
Cook over low heat, covered, for 8 minutes, shaking the skillet once the eggs begin to set to prevent sticking. Eggs should be well set, but still somewhat moist.
Place a warm platter larger than the skillet over the top. Holding both together, invert the Hoppeloppel onto the platter, brown side up. Cut in wedges to serve.