Start the dough. In a sauce pan over medium heat, add the butter, 4 tbsp sugar, and salt. Stir. Once the butter has melted, add the sour cream and heat to luke warm, about 105 degrees.

Meanwhile, in a mixing bowl, add 1/4 cup warm water, yeast, and 1 tbsp sugar, then stir. Allow the yeast to sit for about five minutes, until it has been activated. If the yeast does not become active, toss out the mixture and start with a new packet of yeast. Once the yeast is active, whisk in the warm butter and sour cream mixture, the egg, and 1 cup of flour. Whisk until smooth or use a stand mixer on low.

Begin mixing in small amounts of flour until you form a soft dough. This will generally take about another 2 cups of flour, just go by touch. Using a well oiled dough hook on your stand mixer, knead the dough for 5-10 minutes.

Place the ball of dough into a large well-oiled bowl, then flip the dough so all of the surface area of the dough is oiled. Cover the bowl with oiled plastic wrap (oiled side down) and a hand towel, then set the bowl in a warm draft-free area and allow the dough to rise until it has doubled in size, about 1 hour.

While the dough is rising make the filling (this can also be done in advance). Place the frozen berries, lemon juice, 1/4 cup sugar, and pinch of salt in a saucepan over medium-high heat. Cook the berries for about 10 to 15 minutes, stirring often, until the berries have broken down and the liquid will thickly coat the back of the spoon. It may be necessary to assist some of the larger strawberries in the breakdown process by smooshing them with a spoon.

While the berries are simmering away, add the softened cream cheese and 1/8 cup of sugar into a mixing bowl. Cream the mixture together until smooth. Add in the sour cream, egg, and lemon zest and mix until thoroughly blended. Set the cream cheese mixture aside. Once the berries are finished, transfer them into a bowl to cool for about 15 minutes. After 15 minutes, refrigerate the berries until the dough has finished rising, so they have more of a chance to firmly set.

Once the dough has doubled in size, pour it out onto a lightly floured counter. Lightly flour the top of the dough and a rolling pin. Roll the dough out into a rectangle about 18 inches long and 7 or so inches wide.

Spread the cream cheese mixture evenly over the dough, leaving a 1 inch border around the outside of the dough. Next, evenly spread a thin layer of the berry mixture over the cream cheese layer. Roll the cake up, in a jellyroll-esque fashion, starting by rolling the unfilled border of the dough closest to you over the filling, and carefully begin to roll the dough up into a log. When you have only a few inches left, take the unrolled part and complete the log by gently lifting and pressing the remaining part of the dough up on to the log, so it's seam side-up. Carefully press on the seam to ensure a solid bond. Move the log to a piece of parchment paper and very carefully work the two ends of the log together to form an oval, then press the doughy edges together to completely seal the cake into an oval.

Slide the parchment paper that the king cake is on, onto a large movable surface, such as a large cutting board or a sheet pan. Line a sheet pan with parchment paper then place the sheet pan, parchment side down, on top of the king cake to form a king cake sandwich. Trying not to smash the cake, quickly flip the sandwich over and lift off the top cutting board or sheet pan. Gently peel back the parchment paper, and voila!, the king cake is transferred to a parchment-lined sheet pan, seam side down, and ready for its second rise and the oven.

Recover the cake with greased plastic wrap and a hand towel and allow it to rise for another 30 minutes (I also put a greased glass in the center of the cake so it wouldn't rise and close the hole in the center). Bake the cake at 375 degrees in the upper 1/3 of the oven for about 25 minutes, or until the cake is golden brown. Immediately transfer the cake to a cooling rack after removing it from the oven. This is most easily done by sliding the parchment paper onto the rack directly from the sheet pan. Allow the cake to cool for at least 20 minutes before icing the cake.

Once the cake has cooled for 15 minutes, make the icing. Whisk together the powdered sugar, salt, vanilla, melted butter, and milk until smooth. You want the icing to be able to drizzle easily but not just run right off the cake, so if the icing is too thin, just whisk in more sifted powdered sugar and if the icing is too thick whisk in a touch more milk.

After the cake has had a chance to cool, remove the parchment and move the cake to whatever platter you wish to serve it on. Cut several strips of parchment paper a few inches wide and tuck it underneath the edges of the cake for easy clean up after decorating. At this point, stick a dried bean or little plastic baby into the cake through the bottom. It's tradition in Louisiana that who ever gets the baby has to spring for the next cake! Else where, it's a sign of good luck. Drizzle the icing evenly over the cake and allow it to ooze down the sides. Before the icing has a chance to set, sift on rotating strips of colored sugar. Carefully remove the pieces of parchment paper. King cake is fantastic eaten warm or at room temperature.