Italian tomato paste (try to find the kind in the "toothpaste tube", so much better than having to open a tin which never gets used up before it goes bad)
die Zubereitung:
Saute garlic lightly in a bit of olive oil - it shouldn't brown. Add tuna (drained) and capers, and saute for a few minutes. Stir in tomato paste, add a generous grind of black pepper, and toss with pasta of your choice (actually, I wuoldn't use this kind of sauce on homemade noodles - definitely a factory pasta sauce!)