4 cups chopped Vidalia onions 
3 Tbsp. (1 1/2 oz.) salted butter 
1 (5 oz.) pkg. fresh baby spinach, coarsely chopped 
1 tsp. salt, divided
1/2 tsp. black pepper, divided
1 (16 oz.) container sour cream
2 Tbsp. chopped fresh chives

Melt butter in a large nonstick skillet over medium heat; add onions and cook, stirring often, until golden and very tender, 20-30 minutes.  Gradually add spinach, stirring just until wilted, about 1 minute.  Sprinkle with 1/2 teaspoon salt and 1/4 teaspoon pepper.  Remove from heat and let stand 30 minutes.

Stir together onion and spinach mixture, sour cream, and chives in a medium bowl.  Stir in the remaining 1/2 teaspoon salt and 1/4 teaspoon pepper.  Cover and chill 30 minutes or up to 2 days.

Serve with chips and veggies