3 tablespoons butter
1/2 white onion, chopped
2 cloves garlic, minced
12 eggs
1/2 cup milk
6 croissants, split - tops set aside and bottoms torn into 1-inch pieces
2 green onions, thinly sliced
4 ounces smoked salmon, chopped
1 cup shredded Monterey Jack cheese
1 cup shredded Swiss cheese
1 cup shredded mozzarella cheese
2 tablespoons chopped fresh dill
1 teaspoon salt
freshly cracked black pepper to taste