Chop the onion half and garlic and sauté in a pan without fat until translucent. Clean the spinach leaves, add to the pan and sauté briefly until the spinach has collapsed. Add the ricotta and let it melt.
Cut the chicken fillets in a fan shape and place them on a baking sheet with baking paper. Pour the spinach and ricotta mixture into the slices. Salt and pepper. Put some cheese on top. Scatter paprika on top.