Nadia Lim's sticky date pudding with butterscotch sauce

Ingredients

• 2 1/2 cups pitted dried dates
• 1 cup water
• 1 tsp baking soda
• 60 g butter
• 2 eggs
• 1/3 cup sugar
• 1/2 tsp salt
• 1 tsp vanilla extract
• 1 1/2 cups plain flour
• 1 1/2 tsp baking powder
• Whipped cream, custard or ice cream, to serve
• Butterscotch sauce
• 150 g butter
• 3/4 cup cream
• 1 cup brown sugar