1Peel potatoes and cut into 1/2-inch cubes.
2Rinse with cold water. Drain.
3Pat potatoes dry with kitchen towels.
4Pour oil into heavy deep skillet to depth of 3/4-inch.
5Heat over medium-high heat until thermometer registers 375F.
6Working in batches, add potatoes to skillet; cook until light golden, about 15 minutes.
7Using slotted spoon, transfer potatoes to paper towels. Cool.
8Melt 1 tablespoon butter in heavy large skillet over medium-high heat.
9Add onions and paprika and saute until onions are golden, about 5 minutes. (Can be prepared 8 hours ahead. Cover separately and keep at room temperature).
11Melt remaining 1 tablespoon butter in skillet with sauteed onions over medium-high heat.
12Add potatoes and saute until golden brown, about 3 minutes.
13Season mixture to taste with salt and pepper.
14Spread mixture on heavy large baking sheet.
15Bake until potatoes are cooked through and crisp, about 15 minutes.