Double Ginger Sticky Toffee Pudding

Name: Double Ginger Sticky Toffee Pudding
Ingredients: ½ cup (1 stick) unsalted butter, room temperature, plus more for pan; 2 cups all-purpose flour, plus more for pan; 10 ounces Medjool dates, chopped (about 2 cups); 1 teaspoon baking soda; 2 teaspoons baking powder; ½ teaspoon kosher salt; 1 cup (packed) dark brown sugar; 2 teaspoons finely grated peeled ginger; 3 large eggs, room temperature; ½ cup chopped crystallized ginger; 1 cup heavy cream; ¾ cup (1½ sticks) unsalted butter; 1 teaspoon kosher salt; Demerara sugar (for serving); A 9-cup Bundt pan