1. Grease a 9 x 13 baking dish with butter, line bottom with parchment.
2. In a small saucepan, bring the beer to a boil. Remove the pan from heat and stir in the baking soda. It will fizz up a lot. Pour the beer mixture over the pitted dates. Set aside to cool to room temperature.
3. Once cool, remove the dates to a food processor and add a little of the beer mixture. Process until a paste is formed. Gradually add the rest of the liquid through the feed tube. The mixture will be smooth, dark and glossy. Set aside.
4. Preheat the oven to 350°F.
5. In the bowl of a stand mixer fitted with the whisk beater, beat the butter, sugar, and vanilla on medium speed until light and fluffy. In a small bowl, whisk the eggs. With the mixer on medium, gradually add the eggs in three additions, scraping down the sides of the bowl after each addition.
6. In a medium bowl, whisk together the flour, baking powder, salt, cinnamon and nutmeg. Add one third of the flour mixture to the batter and mix on low speed for 10 to 15 seconds just until incorporated. Scrape down the sides of the bowl. Add half the date mixture and mix just until incorporated, about 15 seconds. Repeat with another third of the flour, then the remaining date mixture, and finally the remaining flour. Mix just until the batter is uniform in color and no streaks remain. Scrape the sides of the bowl as needed. Using a silicon spatula, scrape the batter into the prepared pan and smooth the top. The pan will be about one third full.
7. Bake for 25-30 minutes, or until a cake tester comes out clean. While the cake is baking, make the toffee sauce.
8. Let the cake cool for 10 minutes in the pan on a wire rack. You can then either unmold the cake, or just cut (into 12 pieces) and serve from the cake pan. Serve each slice warm, topped with about 3 tablespoons of the toffee sauce. Top with vanilla ice cream or honey sweetened whipped cream.

For the toffee sauce

1. In a small saucepan, place the brown sugar and butter. Scrape the vanilla bean seeds into the pan and add the pod. Bring the mixture to a boil over medium heat, stirring constantly. Remove the pan from the heat and stir in the heavy cream, lemon juice, and salt. Let cool for a couple of minutes before removing the vanilla bean and serving.
2. Serve this warm! If you aren’t eating this all at once, the cake and sauce can be warmed in the microwave pretty easily. Store the sauce in the fridge and the cake tightly wrapped at room temperature.