On a clean work surface, mound the flour and create a well in the center. Crack the eggs into the well. Using a fork, gently beat the eggs, gradually incorporating the flour from the edges. Once the mixture becomes too thick to mix with a fork, use your hands to knead the dough. Knead for about 8 to 10 minutes until the dough is smooth and slightly firm. Wrap the dough tightly in plastic wrap and refrigerate for about 1½ hours.

While the dough chills, prepare the filling. In a large bowl, combine the ricotta, grated Parmesan, and chopped basil. Stir until well blended. Cover and refrigerate.

Remove the dough from the refrigerator and divide it into 4 equal parts. Working with one piece at a time, lightly flour the surface and roll the dough through a pasta machine, starting from the widest setting and gradually thinning to about 2 millimeters thick (setting 6 or 7). Alternatively, roll manually with a rolling pin, dusting lightly with flour as needed to prevent sticking.

Using a round cutter, cut out circles about 8 centimeters (3 inches) in diameter. Place a half tablespoon of the cheese filling in the center of each circle. Fold the dough over into a half-moon shape and press the edges firmly to seal, ensuring no air bubbles remain. Bring the two corners of the half-moon together and pinch to form the traditional tortellini shape. Set the shaped tortellini on a lightly floured tray.

To prepare the sauce, melt the butter in a large skillet over medium heat. Add the minced garlic and sauté for about 30 seconds, until fragrant but not browned. Add the spinach and cook until wilted and the liquid has evaporated. Pour in the cream and bring to a gentle simmer. Reduce slightly until the sauce thickens. Using a blender or immersion blender, purée the sauce until smooth. Return to the skillet and season with salt and freshly ground black pepper.

Bring a large pot of water to a boil and season with a teaspoon of salt. Gently drop the tortellini into the water and cook for about 5 minutes, until they float to the surface and are tender. Reserve ½ cup of the cooking water, then drain the tortellini using a slotted spoon.

Transfer the tortellini into the sauce, tossing gently to coat. If the sauce is too thick, add a splash of the reserved pasta water to loosen it. Serve immediately on warmed plates.