Sticky Toffee Pudding Cake

Name: Sticky Toffee Pudding Cake
Ingredients: Nonstick cooking spray, for the pan; 1 1/2 cups chopped dates; 1 cup boiling water; 1 cup granulated sugar; 1/2 cup (1 stick) unsalted butter, softened; 3 large eggs; 2 teaspoons vanilla; 2 cups all-purpose flour; 2 teaspoons baking powder; 1 teaspoon baking soda; 1/2 teaspoon salt; 1 1/2 cups muscovado brown sugar; 1 1/2 cups (3 sticks) unsalted butter, softened; 1 cup heavy cream; 1 tablespoon vanilla; 1/4 cup crushed toffee bar or toffee chips, such as Heath Bar, for garnish