Add the blueberries, sugar and cornstarch to a medium pot.

Cook over medium heat for 20-25 minutes until thick and the jam measures out to about 3/4 cup (180 ml).

Remove from the heat, transfer to a bowl and let the jam cool. Set aside 2 tbsp of jam for the frosting.

To start, bloom your yeast. Mix your active dry yeast, sugar, and warm milk together and let sit for 10 minutes until foamy on top.

Next, in a large bowl of a stand mixer with a whisk attachment, mix flour, salt, and sugar together.

To the dry ingredients, add the whisked eggs, vanilla, lemon zest, and softened butter and mix.

Add in the yeast mixture and mix until everything is blended. Switch to a dough hook and knead on medium speed for 7-10 minutes until the dough pulls away from the edges of the bowl, forms a ball and springs back when pressed.

Form the dough into a ball. Place the dough in a large, greased bowl. Cover with plastic wrap or a kitchen towel and place in a warm place to rise for 1-1 ½ hours, or until the dough doubles in size.

While the dough rises, make the filling by mixing butter, brown sugar, white sugar, lemon zest, lemon juice, and salt together in a small bowl.

Grease a 9x13 inch casserole dish and set aside.

Once the dough has had a chance to rise, punch the dough to release the air, remove it from the bowl and roll it out on a lightly floured surface.

Roll the dough into about an 18 x 12 inch rectangle. It should be about ¼ inch thick.

Next, spoon the prepared lemon filling over the dough and spread it evenly with an offset spatula.

Then, spoon the blueberry jam over the lemon filling and spread it evenly with an offset spatula.

Roll up the dough tightly into a long log shape starting from the end closest to you.

Cut off a bit of the ends to make the log even. Cut 12 rolls about 1 ½ inches wide using unflavored floss or a very sharp knife.

Place the rolls in the greased 9x13 inch casserole dish and pour room temperature heavy cream in between each roll.

Cover them with plastic wrap and let them proof in a warm spot for about an hour, or until they have doubled in size.

Preheat the oven to 350 degrees F (175 degrees C) about 15 minutes before the rolls are done proofing.

Once the rolls have proofed, bake for 22-25 minutes, or until a light golden color.

While they bake, make the cream cheese frosting by adding the softened butter to a medium bowl and mixing it on high speed with an electric mixer until pale and fluffy.

Add in the cream cheese and mix until combined on medium speed.

Sift the powdered sugar into the mixture a little at a time and mix on low speed until all is combined.

Then add in the lemon zest and blueberry jam and combine on low then high speed until the frosting is fluffy.

Let the rolls cool for 5 minutes, then cover the warm rolls with the cream cheese icing. Then serve!