Begina day ahead of early in the day.
In a 1 quart sauce pan, bring the milk to steam over medium-high heat. Remove the pan from the stove and the milk to cool for 5 minutes.
In a large mixing bowl, stir together the warmed milk, yeast, and the first measurement of bread flour to create a thick dough.
Cover the mixing bowl with a clean kitchen towel and place it in a warm area of your kitchen. Allow the sponge to ferment for 30 minutes.
After the sponge has finished fermenting, cream together the butter and the granulated sugar in the bowl of a stand mixer fitted with the paddle attachment (or in a large mixing bowl using a hand mixer).
Beat the two ingredients together on medium-high speed until it looks pale yellow and fluffy- about 5 minutes. Scrape down the bowl twice during mixing.
Add the eggs to the bowl and mix them in on medium speed. The mixture will end up looking curdled.
Add your starter to the bowl and blend for 2-3 minutes, or until the mixture looks smooth.
Switch to mixer's dough hook- or use your hands- and add the salt, ground cardamom and 2 cups of the second measurement of flour to the bowl.
Knead the dough on the second speed until the dough comes together. Gradually add the remaining cup of flour to the bowl and continue kneading for 10 minutes. When finished the dough should feel supple, elastic, and no longer sticky.
Remove the dough from the bowl and lightly grease the bowl with your reserved butter wrappers. Return the dough to the bowl and flip it over to coat the surface of the dough in fat.
Cover the bowl with a clean towel and allow the dough to rise in a warm area for 1 hour.
Cover the bowl with plastic wrap and refrigerate, anywhere from 3-24 hours.
This step is optional, but recommended for easier handling of the soft dough.
In a mixing bowl, blend together the cream cheese and powdered sugar on low speed until smooth.
Add the lemon juice, vanilla extract, egg, and salt to the bowl, and blend, once more, until smooth.
Set the filling aside.
In a separate bowl, combine the dark brown sugar and the ground cinnamon together. Set this to the side as well until your dough is ready to roll and fill the dough.
Set the bowl of dough onto the countertop a 1/2 hour prior to rolling it out. This makes rolling it out easier.
Lightly flour your work surface with bread (or all-purpose flour). Use a rolling pin to roll the dough out into a big rectangle (about 20"x10" inches).
Spread enough of the cinnamon-sugar mixture onto the surface of the dough to cover it- leaving a 1" margin on the long side closest to you.
Roll the dough into a log-shape beginning with the long side farthest from you. Roll towards yourself making sure your roll is tight and uniform.
When you get to the uncovered margin, rock the roll firmly to seal the dough to the roll.
Use your fingers to pinch the roll closed.
Fold the ends over (to prevent the sugar from coming out) and roll it between your hands and the counter to stretch it out to about 30".
Use an offset spatula to spread the cream cheese filling out on a rectangle of dough (rolled the same way as before). Remember to leave the margin for sealing!
Roll, pinch, and stretch the same way you did with the first roll. This roll will be looser than the previous roll because of the filling. Try not to puncture the dough or the filling will ooze out.
To form the wreath of dough: pinch together each end of the rolls of dough to join them.
Twist the two rolls of dough together until you get to the opposite ends. Form the twisted rope into a wreath and transfer it to an inverted sheet pan that's been lined with parchment paper.
Cover the wreath with a kitchen towel and allow it to rise for 30 minutes in a warm area of your kitchen.
Pre-heat your oven to 350°F.
Make the egg wash by whisking together the egg and cold water until smooth.
Once the dough has risen, brush egg wash where the ends of dough overlap and pinch them together to seal the ring.
Brush the rest of the dough with the egg wash. This will give your baked loaf a beautiful color.
Bake the loaf for 30 minutes, or until the bread is golden brown and sounds hollow when tapped (rotate your pan half-way through baking to ensure it browns evenly).
Combine the powdered sugar, light corn syrup, and the vanilla extract in a saucepan, or bowl.
Add hot water (a teaspoon at a time) to thin the glaze slightly.
If you prefer a thin glaze, heat the mixture over low heat until it is runny. If you want a thicker glaze prefer my glaze leave it un-heated. A thick glaze should have the consistency of molasses.
Once the King Cake has finished baking, remove the pan from the oven and allow the bread to cool completely.
Use a small ladle to spoon the glaze onto the surface of the King Cake.
Decorate with a generous amount of sprinkles, sanding sugar, or chocolate shavings.
Slice and serve. The King Cake is best enjoyed a day or two after baking.