Preheat the oven to 250°. Melt ¼ pound of butter in a large heavy skillet. Lightly salt half of the frog’s legs and sprinkle with cayenne. Dredge lightly in the flour. Sauté the floured frog’s legs over moderately high heat until golden. Sprinkle with half of the rosemary. Keep warm in the oven.

Repeat the process with the remaining frog’s legs and keep warm.

To deglaze the pan, add the wine and cook over high heat, scraping up the brown bits that cling to the bottom of the pan until the liquid is reduced by half. Strain the sauce over the frog’s legs and serve.