Add the onions and garlic to the pan and sauté until the onions are translucent, about 10 minutes.
While they are sautéing, process the walnuts and mint in a food processor until the walnuts are finely ground. Stop, take a moment to smell the walnut/mint mixture. It is outrageous. Now add this mixture to the pan with the onions and garlic. Next, add the tomato paste, wine and 1 cup of water to the pan and stir together. Return the hens to the pan, cover, and simmer for 20 minutes.
Turn the hens over and continue simmering until the hens are cooked through, about 20 minutes more.
The recipe in Bon Appetite called for removing the hens and keeping warm on a platter covered with tin foil and then reducing the liquids in the pan to create a sauce consistency. I found that this was not necessary and the onion/garlic/walnut/mint was ready to use as a sauce.
We served this dish with couscous and green beans so I plated a hen halve on top of a mound of couscous and poured the sauce on top. The beans were plated on the side. It not only looked and smelled great, the flavor was incredible.