Preheat your oven to 350°F (175°C). Grease and flour a 9×13 inch baking pan.

In a bowl, combine the chopped dates and boiling water. Let stand for 10 minutes to soften. Mash the dates with a fork until mostly smooth.

In a large bowl, cream together the softened butter and brown sugar until light and fluffy.

Beat in the eggs one at a time, then stir in the vanilla extract and mashed dates.

In a separate bowl, whisk together the flour, baking soda, and salt.

Add the dry ingredients to the wet ingredients alternately with the buttermilk, beginning and ending with the dry ingredients. Mix until just combined.

Pour the batter into the prepared baking pan and spread evenly.

Bake for 30-35 minutes, or until a wooden skewer inserted into the center comes out clean.

While the cake is baking, prepare the toffee sauce. In a saucepan, melt the butter over medium heat. Stir in the brown sugar and cook, stirring, until the sugar is dissolved.

Bring the mixture to a boil, then reduce heat and simmer for 5 minutes, stirring occasionally.

Remove from heat and stir in the heavy cream and vanilla extract.

Once the cake is baked, let it cool in the pan for 10 minutes. Poke holes all over the top of the cake with a skewer.

Pour about half of the warm toffee sauce over the hot cake, allowing it to soak in.

Serve the cake warm with the remaining toffee sauce on the side.