How to Make It
In a blender, puree the tomato with the vinegar, mustard and garlic. With the blender on, slowly pour in the olive oil until smooth. Scrape the sauce into a bowl. Stir in the chopped anchovies, olives and capers and season the puttanesca with salt and pepper.
In a medium saucepan of boiling salted water, blanch the sugar snaps until crisp-tender, about 2 minutes. Drain and refresh in cold water. Reserve the blanching water.
Heat the olive oil in a large skillet. Add the garlic and shallot and cook over low heat until softened, about 2 minutes. Add the tomato and sugar snaps and cook, stirring, for 3 minutes. Add the thyme and capers and season with salt and pepper. Remove from the heat.
Preheat the oven to 300°. Bring the sugar snap blanching water back to a boil. Add the fennel quarters and cook until tender, about 8 minutes. Drain and let cool. Pat dry with paper towels.
Put the flour in a shallow bowl and season generously with salt and pepper. Crack the eggs into another shallow bowl and beat them with the milk. In a medium saucepan, heat 1 inch of vegetable oil to 350°. Dredge the fennel in the flour, then dip the wedges in the beaten eggs and dredge again in the flour. Working in 2 batches, fry the fennel, turning once, until golden brown, about 3 minutes. Transfer the fennel to a rack set over a rimmed baking sheet and keep warm in the oven.
Light a grill or preheat a grill pan. Rub the tuna steaks with olive oil and season with salt and pepper. Grill over high heat until deeply browned outside and rare in the center, about 3 minutes per side. Transfer the tuna to a cutting board and cut each steak into 1/3-inch-thick slices.
Reheat the sugar snaps and spoon them onto plates. Lay the sliced tuna on the plates and drizzle the puttanesca sauce around the fish. Set 2 fennel fritters on each plate, garnish with the whole anchovies and serve at once.
White marinated anchovies, called alici, are available at specialty food shops.