Heat the oil in a large skillet over medium heat. Add the onions and saute' until softened but not colored, 5 to 7 minutes. Stir in the paprika and toss with the onions until they are deeply colored.
Add the peppers and continue to saute', stirring occasionally, for another 10 minutes. Do not allow the vegetables to brown.
Stir in the tomatoes, tomato paste, broth, and salt and pepper. Allow the mixture to boil, reduce the heat, cover, and simmer the peppers until very tender, about 30 to 35 minutes, adding more liquid, a little at a time, if it evaporates.
Off the heat, stir in the vinegar and sugar and allow the mixture to cool.
This can be served warm, at room temperature, or cold.
Serves 4 [as a side dish]
[Variation: Use roasted red peppers instead of fresh. You'll probably find this requires less cooking time, and requires more sugar to take the edge off the roasted red peppers and prevent them from dominating the dish. - Curtis]
[From _Please_To_The_Table_-_The_Russian_Cookbook_ by Anya von Bremzen and John Welchman]