Make toffee sauce by combining 1¼ cups of cream, butter, corn syrup, and sugar in a medium saucepan. Bring to a boil. Stir frequently and cook until the mixture turns a deep amber color (35 to 40 minutes).
Whisk in the remaining heavy cream and then strain the sauce through a sieve into a glass bowl.
In another small saucepan, simmer dates in water on low heat for about 15 minutes (the dates should be soft). Once done, add the dates and excess liquid to a food processor and puree until smooth.
Preheat the oven to 350°F. Butter 6 ramekins and set aside.
Whisk flour, baking powder, baking soda, and salt in a small bowl. Set aside.
In another bowl, beat the butter and brown sugar together until light and fluffy. Add the egg and vanilla, followed by the date puree. Add the dry ingredients and beat until smooth.
Spoon batter into ramekins, making sure to smooth the tops. Bake for 20 minutes or until a toothpick inserted into the center comes out clean. Let cool for 10 minutes.
Trim the tops of the cakes to be level with the tops of the ramekins. Remove the cakes and then cut each cake in half horizontally. Cutting the cakes in half gives the warm toffee sauce more places to soak into the cake, so the finished pudding has sauce throughout instead of only on top.
Clean out ramekins and spoon 1 tablespoon of toffee sauce into the bottom of each ramekin. Layer the bottoms of the cakes back in the ramekins, followed by another tablespoon of toffee sauce and then the top piece of cake. Add another tablespoon of toffee sauce and spread evenly.
Place ramekins on a baking sheet and bake for 10 minutes.
Let cool slightly, then turn each cake out of the ramekin onto a dessert plate. Top with warmed toffee sauce and whipped cream.