Romanian Spinach Soup with Eggs

Name: Romanian Spinach Soup with Eggs
Ingredients: 2 lbs fresh spinach (1 kg, Note 1); 1 tablespoon olive oil; 1 medium onion; 2.5 oz bacon (or pancetta, 75 g, Note 2); 1 small carrot; 1 small piece of celeriac (2 oz/ 60 g, Note 3); ½ teaspoon sweet paprika; 6 cups vegetable broth (or chicken stock, 1.5 liter); 3 large garlic cloves; ¼ cup heavy cream (60 ml); 1 heaped teaspoon all-purpose flour; 2-3 tablespoons fresh lemon juice (to taste); 1 handful dill; fine sea salt and pepper; 4 eggs; 1 teaspoon butter