Savory Dutch Baby Pancake with Salmon and Fried Egg

Name: Savory Dutch Baby Pancake with Salmon and Fried Egg
Ingredients: 3 large eggs; 3/4 cup whole milk; 4 tablespoons unsalted butter , melted and divided; 1/2 cup all-purpose flour; 3 tablespoons buckwheat flour ( whole wheat flour ); 1/4 teaspoon fine salt (1/2 teaspoon if using Kosher salt); 1 tablespoon unsalted butter; 4 large eggs; 4 ounces thinly sliced smoked salmon; 4 small sliced ripe tomatoes; 4 tablespoons sour cream; 2 tablespoons chopped fresh parsley; 4 tablespoons chopped scallions , including some of the green part; Freshly ground black pepper , to taste