Indulgent Potatoes Lyonnaise

INDULGENT POTATOES LYONNAISE
4 medium russet potatoes, peeled and thinly sliced
Kosher salt/black pepper to taste
6 T. butter, divided
1 medium onion, thinly sliced
1 T. minced fresh rosemary
1. In large saucepan or Dutch oven, combine potatoes, salt and pepper and enough cold water to cover the potatoes by an inch.
2. Bring water to a boil, then reduce to low.
3. Simmer potatoes until slightly cooked but still al dente, about 3-4 minutes.
4. Drain potatoes.
5. In large skillet, melt 3 T. butter.
6. Add onion and cook, stir frequently, until golden brown, 10-12 minutes.
7. Take the onion mixture out and set aside.
8. In same skillet melt remaining butter.
9. Add potatoes and cook, stir occasionally, until golden brown, about 8-10 minutes.
10. Add the cooked onions, rosemary and season to taste. Toss to combine.
11. Cook until heated through.
12. Serve.