Serves 6 to 8.
accompaniment: vanilla ice cream
Preheat oven to 375°F. and butter and flour an 8-inch square baking pan (2 inches deep), knocking out excess flour.
Coarsely chop dates and in a 1 1/2- to 2-quart saucepan simmer dates in water, uncovered, 5 minutes. Remove pan from heat and stir in baking soda. (Mixture will foam.) Let mixture stand 20 minutes.
While mixture is standing, into a bowl sift together flour, baking powder, ginger, and salt. In a large bowl with an electric mixer beat together butter and sugar until light and fluffy. Beat in eggs 1 at a time, beating well after each addition. Add flour mixture in 3 batches, beating after each addition until just combined. Add date mixture and with a wooden spoon stir batter until just combined well.
Pour batter into baking pan and set pan in a larger baking pan. Add enough hot water to larger pan to reach halfway up sides of smaller pan and bake in middle of oven until a tester comes out clean, 35 to 40 minutes. Remove smaller pan from water bath and cool pudding to warm on a rack.
Make sauce while pudding is cooling:
In a 1 1/2- to 2-quart heavy saucepan melt butter over moderate heat and add brown sugar. Bring mixture to a boil, stirring occasionally, and stir in cream and vanilla. Simmer sauce, stirring occasionally, until thickened slightly, about 5 minutes. Cool sauce to warm.
Cut warm pudding into squares. Serve pudding with ice cream and warm sauce.