Prep the pan and oven. Heat the oven to 180°C/160°C fan (350°F). Line a 23 x 33 cm (9 x 13 inch) traybake tin with baking parchment, leaving a slight overhang for easy lifting.

Soak the dates. Put the chopped dates in a bowl. Pour the boiling water over them and stir in the bicarbonate of soda. Let it sit for 10 minutes to soften. The mixture will foam a little and thicken.

Cream butter and sugar. In a large bowl, beat the butter and brown sugar together until light and fluffy, about 2–3 minutes. This helps create a tender, airy crumb.

Add eggs and vanilla. Beat in the eggs one at a time, mixing well after each. Stir in the vanilla. If the mixture looks slightly curdled, don’t worry—it will come together once you add the flour.

Combine dry ingredients. In a separate bowl, whisk the flour, baking powder, and salt to break up any lumps and distribute the leavening evenly.

Bring the batter together. Add half the dry mixture to the butter mixture and mix on low just to combine. Stir in the soaked dates and any liquid from the bowl. Add the remaining dry mixture and fold gently until no flour streaks remain. Do not overmix.

Bake. Transfer the batter to the lined tin and smooth the top. Bake for 28–35 minutes, until the cake is risen, golden, and a skewer inserted into the center comes out with a few moist crumbs.

Make the toffee sauce. While the cake bakes, put butter, brown sugar, and cream in a saucepan. Warm over medium heat, stirring, until the sugar dissolves and the sauce gently bubbles, 3–4 minutes. Remove from heat and stir in vanilla and a pinch of salt.

Soak the cake. As soon as the cake comes out of the oven, poke all over with a skewer. Pour about half the warm toffee sauce evenly over the hot cake so it soaks in. Reserve the rest for serving.

Rest, slice, and serve. Let the cake sit for 15–20 minutes to absorb the sauce. Lift from the tin, slice into squares, and serve warm with extra toffee sauce. Add ice cream or custard if you like.