In 1-quart saucepan, heat ¾ cup water to boiling over high heat.
Remove saucepan from heat and stir in dates, instant coffee, and baking soda; let stand 15 minutes.
Meanwhile, on waxed paper, mix flour, cocoa, baking powder, and salt until blended; set aside.
In large bowl, with mixer at medium-high speed, beat 3 tablespoons margarine or butter with granulated sugar until creamy.
Add egg and vanilla, and beat until blended.
With mixer at low speed, alternately add flour mixture and date mixture, beginning and ending with flour mixture; beat just until batter is evenly blended, occasionally scraping bowl with rubber spatula (batter will be thin).
Pour batter into pan; spread evenly.
Bake 18 to 20 minutes, until toothpick inserted in center comes out clean.
Meanwhile, in 1-quart saucepan, combine brown sugar, cream, and remaining 2 tablespoons margarine or butter; heat to boiling over medium heat, stirring frequently.
Boil 1 minute, stirring.
Remove saucepan from heat and set aside.
Remove pudding from oven.
Turn oven control to broil.
Pour brown-sugar mixture over hot pudding; spread evenly.
Return pudding to oven; broil at closest position to heat source 30 seconds or until bubbly.