Preheat oven to 375 degrees F. Grease an 8-cup gratin dish.

In large pan over medium heat, melt butter. Add onions and sauté 2 minutes. Add flour and cook 1 minute, stirring constantly. Stir in milk and bring to simmer. Add Just Peas and Just Green Onions. Simmer 2-3 minutes, until peas soften. Fold in cheeses; season with salt and pepper. Pour into prepared dish. Sprinkle with panko crumbs, additional cheeses and bacon bits. Bake until peas are bubbly and top is golden, about 15-20 minutes. Serve warm.