MAKE THE DATE CAKE
Preheat oven to 350°F (175°C). Grease and line an 8-inch square pan or similar baking dish with parchment paper.
Place chopped dates in a medium heatproof bowl. Bring the milk to a boil, then immediately pour it over the dates. Stir in the baking soda (the mixture will bubble up) and let it sit to soften while you prepare the rest.
In a large mixing bowl, cream together the softened butter and light brown sugar until light and fluffy.
Beat in the eggs one at a time, then stir in the vanilla extract.
Add the pumpkin purée and the date mixture to the bowl and mix until fully combined.
In a separate bowl, whisk together the flour, baking powder, salt, and pumpkin pie spice.
Gently fold the dry ingredients into the wet mixture until just combined — do not overmix.
Spread batter evenly into the prepared pan and bake for 30 to 35 minutes, or until a toothpick inserted in the center comes out clean.
MAKE THE TOFFEE SAUCE
While the pudding bakes, melt the butter in a medium saucepan over medium heat.
Stir in the dark brown sugar, heavy cream, cinnamon, salt, and vanilla.
Bring to a gentle simmer, whisking constantly, until smooth and slightly thickened, about 5–7 minutes. Remove from heat.
SERVING
Let the pudding cool for about 10 minutes. Optional: poke holes across the top with a skewer or fork. Pour some of the warm toffee sauce over the pudding to soak in.
Slice into squares or spoon into bowls, topping each portion with extra toffee sauce.
Serve warm with a scoop of vanilla ice cream or a dollop of whipped cream for the full experience.