Prep a 9x5 loaf tin by greasing with butter and lining with a parchment sling.

Make the caramel. Have all ingredients measured out and ready to go. In a medium saucepan, combine the sugar, corn syrup and water. Cook over medium heat, undisturbed, until the sugar is dissolved, the caramel reaches a deep amber color, and you begin to see wisps of smoke.

Immediately whisk in the heavy cream, then the butter. Whisk the mixture vigorously, as it will begin to bubble up and can pour over the sides.

Remove from heat and stir in the vanilla and salt until smooth. Set aside to cool.

Mix together the gingersnap crumbs, melted butter, and salt until it resembles wet sand. Pour half of the crumbs into the dish and tamp them down. Set in the freezer to firm up completely.

Make the ice cream. In a medium saucepan, combine the pumpkin, cinnamon, and pumpkin spice. Cook on medium-low until the mixture starts to stick to the bottom of the pot and looks noticeably drier and darker, about 5-7 minutes. Remove from the heat and allow to cool.

In a stand mixer or with a handheld mixer, whip the cream just until it forms stiff peaks when the beater is lifted out.

Combine the sweetened condensed milk, cream cheese, and pumpkin puree in a separate, medium bowl. Add one-third of the whipped cream, folding it into the sweetened condensed milk mixture. Repeat 3 more times with the rest of the whipped cream. Make sure to be gentle, or you will beat all the air out.

Pour half the ice cream into the tin with the crust. Sprinkle the remaining crumbs onto the surface of the ice cream, then pour the cooled caramel evenly over the top. Top with the remaining ice cream and smooth over.

Cover with plastic wrap and freeze for at least 8 hours, but preferably overnight.

Make the cream cheese frosting, if using. Combine the powdered sugar and cream cheese in a bowl.

When ready to serve, top with frosting when the cake is straight out of the freezer. Use the parchment sling to lift the cake out of the tin; you might have to warm up the sides a bit.

Warm up a sharp knife with hot water, slice and serve!