In a bowl, combine 4 beaten eggs, 3/4 cup water, 2 cups sifted all-purpose flour, and 1 1/2 teaspoons salt.
Gradually mix in the remaining 1 3/4 cups flour until smooth.
Divide dough into 2 parts, cover, and refrigerate for 20 minutes.
In a skillet over medium heat, cook 250 grams ground chicken until evenly brown, then drain.
In a food processor, mix the cooked chicken, 3/4 cup chopped spinach, and 2 tablespoons chopped onion.
Transfer the mixture to a bowl and add 3 tablespoons melted butter, 3 tablespoons grated Asiago cheese, 1/4 teaspoon salt, 1/4 teaspoon garlic powder, 1/8 teaspoon ground nutmeg, and a pinch of ground black pepper.
On a lightly floured surface, roll out each part of the dough to 1/8 inch thickness.
Cut the dough into 2-inch squares.
Place about 1 teaspoon of the chicken mixture in the center of half of the squares.
Top with the remaining squares and seal the edges with a moistened fork to form the ravioli.
Bring a large pot of lightly salted water to a boil.
Cook the ravioli in small batches for about 8 minutes or until al dente, then drain and rinse under cold water.
Heat the marinara sauce in a saucepan.
Serve ravioli topped with marinara sauce and 1/4 cup grated Asiago cheese.