Make the Cake:

1. Preheat oven to 350F for Standard Oven or 335F for Convection/Fan. Prepare 2-9″ baking pans by buttering/flouring, or by inserting rounds of parchment paper. (I give my parchment a quick spray!)
2. Into a large mixing bowl of a stand mixer, or a large bowl to use hand-mixer, sift together the flour, baking powder, baking soda, salt, cocoa and sugar.
3. At low speed, add the softened butter. Mix for 1 minute, then add the olive oil. Combine until the mixture has the texture of beach sand.
4. In a small bowl or large measuring cup, stir together the buttermilk, vanilla extract, coffee. Add to the mixing bowl altogether, then mix batter until just incorporated, at low speed. Scrape the bottom and sides of the bowl, then continue to mix for another 30 seconds. This mixture will be very thin.
5. Add the eggs one at a time, mixing well at Medium-High speed between each. Again, batter should be quite thin.
6. Pour the batter into your prepared 9″ baking pans. Place in preheated oven and bake for 26-30 minutes until a tester inserted in the center comes out clean. Cool 10 minutes, then remove cakes from pans to cool completely before filling and frosting.

Make the Frosting:

1. Chop the chocolate. In a heatproof bowl over a saucepan of simmering water, melt the chocolate. Stir occasionally until just melted and smooth. It should not be hot to the touch. Remove from the heat and set aside for 5 minutes or so until it has cooled slightly.
2. Scrape into the bowl of a stand mixer, or a bowl you can use with a hand-mixer. Add the butter and beat until fluffy. This may take awhile, but after 6-10 minutes at high speed, it should become fluffy. See my photo.
3. Beat in the confectioners sugar, buttermilk, and pinch of salt until smooth. Set aside. 

Make the Cookie Dough:

1. Heat treat the flour. Place the flour in a bowl. Microwave 30 seconds. Stir and fluff the flour. Microwave an additional 30 seconds. Stir and fluff. Set aside to cool.
2. In a stand mixer at Medium speed, beat together the butter and brown sugar until fluffy, about 3-4 minutes.Add the vanilla and salt, mixing until just incorporated.
3. At low speed, in alternating additions, add 1 cup flour, followed by half the can of Sweetened Condensed Milk, then the second cup of flour, and remainder of Condensed Milk.
4. Fold in the chocolate chips.
5. Into a parchment-lined and sprayed (or buttered) 8- or 9-inch cake pan, press in half to two-thirds of the cookie dough. The layer should be just under 1/2″ thick. Set aside to use as filling. Refrigerate the rest for later use, or save to decorate top of cake.

Compose the Cake:

1. Place completely cooled bottom layer of cake on serving dish. 
2. Remove the cookie dough layer from its pan. Place atop the bottom cake layer.
3. Place the second cooled cake layer on top of the cookie dough layer.
4. Frost and decorate as desired.