Eggs Florentine in Tomato Cups

Name: Eggs Florentine in Tomato Cups
Cuisine: European, Italian, Mediterranean, Greek
Ingredients: 4 very large tomatoes (8 to 12 ounces each); 1 tablespoon olive oil, plus 2 teaspoons more for brushing; 1/4 cup minced shallots; 1 tablespoon flour; 3/4 cup low-fat milk (1 percent); One 10-ounce package frozen/defrosted spinach, squeezed of all excess liquid, then chopped (even if the frozen spinach was already chopped); 1 ounce (1/3 cup) finely grated Parmigiano-Reggiano cheese; 1/4 teaspoon salt; 1/4 teaspoon freshly ground black pepper; 4 large eggs, at room temperature