PEEL THE POTATOES AND SLICE them lengthwise into quarters or, if large, into 6ths.
Trim the fennel, remove the outer leaves if they're scarred, and cut into wedges 1/2-inch thick or a little wider.
Leave some of the core so that the pieces stay intact.
Cut the tomatoes into large, neat pieces.
Bring a pot of water to a boil, add salt to taste and the potatoes, and boil for 5 minutes.
Remove the potatoes, but save the water.
While the potatoes are cooking, warm the olive oil in a wide pan.
When hot, add the leek, onion, garlic, herbs, a little salt, saffron, orange zest and bay leaves.
Cook slowly over medium heat until the onions have begun to soften, after 6 or 7 minutes, then add the wine.
Let it reduce by approximately half, then add the tomatoes and their juice, the potatoes, fennel, half the parsley and the olives.
Pour in enough of the reserved potato water to cover, bring to a boil and lower the heat.
At this point, you can set the stew aside and finish it later, either in the oven or on top of the stove.
If cooking on top of the stove, cover the pan and cook slowly until the vegetables are tender, about 35 minutes.
If cooking in the oven, preheat it to 375F, cover loosely and bake for about 1 hour, or until done.
Remove bay leaves.
Garnish with the remaining parsley and serve with a bowl of garlic mayonnaise.