1 1/2tspCoarse sea salt for sprinkle on topOptional
Grease and lightly flour a 9- inch square bake pan.
Sift flour, cocoa powder and salt in a medium sized bowl. Discard any clumpy bits and then sift again.
Add the butter to a saucepan and melt it on low until bubbling, then add the dark chocolate and unsweetened chocolate.
Whisk until the chocolate mixture is completely melted. Set aside.
Alternative option if you have an Instant Pot pressure cooker: Select SAUTÉ-Low30 minutesSTART. Add the butter into the Inner pot and melt it until bubbling then add the dark chocolate and unsweetened chocolate. Whisk until the chocolate mixture is completely melted. Press CANCEL. Remove the inner pot and put it aside.
In a large bowl, add the sugar, syrup, and eggs and mix them with an electric mixer on high speed until they are about double in volume and a light pastel yellow color.
Add vanilla extract, kosher salt, cocoa powder, and flour to the batter. Mix on low speed for three minutes. Pause to scrape down the sides and bottom of the bowl, and then mix for another minute until the batter is homogenous.
Pour one-third of the batter into the prepared 9 -inch cake pan and use a silicone spatula to smooth it out.
Give your can of dulce de leche a good stir and then spoon about one-third of the caramel on to the batter. Drizzle on thick stripes and then swirl into the batter using a wooden skewer.
Sprinkle the milk chocolate chunks over the swirled batter, making sure the surface is evenly and generously covered.
Pour on the remaining two-thirds batter. Spoon the rest of the caramel on the top and swirl it up, and then finish with a light sprinkle of coarse sea salt.
Select BAKE on the Omni then set the temperature to 350°F and set time to 45 minutes. Press START and place the cake pan on the cooking pan.
Once the Omni is preheated, insert the cooking pan on the Bake Level into the Omni.
After the baking cycle is finished, check the cake with toothpick inserted in the middle comes out clean. Remove the cake pan and place the cake pan on the rack and cool it off for an hour to room temperature.
Serve with a scoop of ice cream and drizzle caramel sauce if you desire.