Step 1

Make the cake: Preheat oven to 350 degrees. Butter and flour a 9-inch round or a 9-by-13-inch rectangular cake pan.

Step 2

In a food processor, combine dates, ¼ cup boiling water and vanilla. Gradually add remaining boiling water and blend into a smooth purée. (If you add it too fast, the water may overflow and create a mess.) Transfer to a bowl and set aside.

Step 3

In the same food processor bowl, blend butter, sugar and cream until pale and well combined. It won’t fluff up as it would in a mixer, but that’s fine. Add eggs and tahini, and process until you have a pale, smooth  purée.

Step 4

Tip flour, baking soda and baking powder into the food processor and mix until combined. Fold date mixture back in and process until just combined, taking care not to overbeat batter.

Step 5

Scrape batter into prepared cake pan and transfer to oven. Bake until a skewer inserted into center comes out clean, about 45 minutes. (You can start testing at 35 minutes.)

Step 6

Make the toffee sauce: In a small saucepan, combine cream, butter, brown sugar and date molasses, and cook over low heat until butter melts. Increase heat to medium and bring mixture to a boil. Simmer, stirring occasionally until slightly thickened, 2-3 minutes. Remove from heat, add tahini and salt, and give one final stir. The tahini sauce should be warm when served and can be reheated on the stovetop or the microwave. Sauce keeps in the fridge up to 1 week.

Step 7

To serve, place an individual slice of cake on a serving plate, top with ice cream or yogurt, if using, and drizzle with warm sauce.