Heat the oven to 400ºF. Put the raisins in a small bowl, cover them with warm water, and soak for 15 minutes, then drain.
Meanwhile, whisk together the eggs and ¼ cup of the sugar in a large bowl, then add the flour, half-and-half, almond extract, and vanilla extract. Stir to combine. Grease a 10-inch round baking dish or cast-iron skillet with butter, then sprinkle with the remaining scant tablespoon sugar. Distribute the drained cherries and raisins in the dish and pour the batter over them.
Bake until the surface of the clafoutis is golden and the edges are golden-brown, about 30 minutes. Cool, dust with powdered sugar, and serve in wedges, topped with a scoop of ice cream. (Store leftover clafoutis in an airtight container for up to a few days.)
