Mix until smooth. Scrape down the sides of the bowl with a rubber spatula.
Put baking soda and pitted dates in a heat-proof container. Pour boiling water to cover, then let sit for 30 minutes.
Whisk together flour, baking powder, and salt.
Add ⅓ to batter. Mix just until almost incorporated. Scrape the bowl down.
Add in ⅓ date mixture. Add the remaining flour and date puree in thirds, scraping the bowl down after each addition of flour.
Pour batter to ⅔ full into greased ramekins. Bake 25-30 minutes until cake tester inserted in the center comes out with a few crumbs on it. Do not overbake!
Step 10 For toffee sauce:
Bring sugar and butter to a boil in a saucepan. Cook on medium-low heat until sugar is completely dissolved.
Off heat, add cream, salt, and lemon. Return to a simmer and whisk. Set aside until the cake is ready.
Step 12 To serve:
Unmold cake 10 minutes after removing from the oven and spoon warm toffee sauce on top. Serve with whipped cream or vanilla ice cream.
Cake and sauce can be separately stored up to 4 days in the refrigerator. To reheat, warm cake with a little sauce spooned on top in a 180°C / 350°F oven for 5 minutes. Then spoon on more warmed sauce to serve.