Preheat the oven to 350 F, and position a rack in the center of the oven. Lightly grease an 8-inch square baking pan with butter, or spray with non-stick baking spray.
In a bowl, combine the chopped dates with the boiling water and the baking soda. Let stand 10 minutes to soften the dates.
Whisk in the melted butter, brown sugar, eggs and vanilla, then whisk in the flour, baking powder and salt, just until combined.
Spread the cake batter into the prepared pan. Bake the cake for about 25-28 minutes, until the cake springs back when gently touched, or a toothpick or cake tester inserted into the center comes out clean.
Let the cake cool for 15 minutes, then serve warm with the toffee sauce and vanilla ice cream.
While the cake is baking, you'll have plenty of time to make the toffee sauce, so it can cool slightly before serving it with the warm cake.
Notes
Store leftover cake in an airtight container at room temperature for up to 3 days.Reheat pieces of leftover cake for 30-45 seconds in the microwave at 50% power.
Keyword Cake, High Altitude, Pudding, Sticky, Toffee