Pumpkin Flan

In a heavy bottomed sauce pan, dissolve the Cream of Tartar in the water.
Add the Sugar to middle of the pan and turn heat on medium-low. DO NOT STIR! Let the sugar dissolve and come to a simmer. Cook on medium-low heat until the sugar has dissolved into the water completely, and begins to simmer.
Once sugar is dissolved and mixture is simmering, turn the heat to high and allow to cook for about 5 full minutes, until the cooked sugar goes from clear to light golden brown. During this process, it should be boiling; this will help cook out the water.
When it starts to turn a light golden brown, immediately lower the heat to medium-low and keep cooking until it turns a golden brown. Once the edges begin turning golden, you can give it a gentle stir.
Continue to watch and occasionally stir gently until the mixture is a deep amber color.
Remove from heat and pour into bottom of 8" cake pan. Swirly the caramel mixture around so the bottom is evenly coated. Be careful - caramel is extremely hot and will stick and burn.
Once caramel has evenly coated the bottom of the pan, sprinkle 1/4 tsp Cinnamon, Nutmeg, and Allspice on top of the Caramel.
Set Aside.

Add Eggs to a medium mixing bow. Gently beat, taking care not to "fluff" them too much, as you don't want to incorporate air into your flan.
Add Milk, Cream, Pumpkin, Sugar, Spices, Vanilla, and Salt. Stir Gently to combine.

Set an elevated metal trivet, or form one out of foil, in the bottom of a 9x13 baking dish.
Gently pour the Milk/Pumpkin mixture into the Caramel coated cake pan.
Set your Flan onto the trivet. Fill the 9x13 baking dish with water, as high as you can in order to comfortably move it to your oven. Move the whole conglomeration to your oven's middle rack.
Now, turn your oven on to 350℉. Your Flan and water bath will preheat with the oven, which will help prevent cracking of the flan. Sudden temperature changes are the enemy.
Bake for 1 hour and 20 minutes, or slightly longer, depending on your oven. Bake until the flan is puffing up around the edges and longer wobbly in the middle.
Remove from oven to a wire rack. Cool to room temperature. At this point, you can safely put it in the refrigerator, covered with plastic wrap, for at least 3 hours, preferably overnight, before serving.

When ready to serve, take the flan out of the refrigerator. Remove plastic wrap. Run a butter knife around the edge of the pan to loosen.
Place plate/serving tray on top of the flan. Grip both the plate and the pan, and quickly flip everything over. You will see caramel begin to run out of the pan, and hear the flan "plop" onto the tray.
Once flan is out of the pan, scrape any remaining caramel sauce onto the flan.
Cut, and Enjoy!