Preheat oven to 350°F and prepare a 9x13-inch baking dish with parchment and nonstick spray.
Mix wet ingredients: In a large bowl, whisk together molasses, hot water, both sugars, eggs, melted butter, and vanilla.
Combine dry ingredients: In another bowl, whisk flour, baking powder, baking soda, salt, and spices.
Blend together: Add dry ingredients to the wet and whisk until just combined — don’t overmix.
Bake: Pour into your prepared pan and bake for 35–40 minutes, or until a toothpick comes out clean.
Poke & soak: While warm, use the handle of a wooden spoon to poke holes across the top. Pour caramel sauce evenly over the cake so it sinks in.
Chill: Refrigerate for at least 2 hours so the caramel can soak into every bite.
Make the frosting: Beat butter, vanilla, molasses, powdered sugar, and cream together until fluffy.
Frost & decorate: Spread frosting over the cooled cake and sprinkle crushed gingerbread cookies on top.
Serve & store: Cover and refrigerate leftovers for up to 3 days — it tastes even better the next day!