Preheat the oven to 350 degrees F
Grease and flour 3 (9 inch ) round cake pans.
In a large bowl, beat butter and sugar together at medium speed just until fluffy.
This should take about 3 to 4 minutes and if your using a stand mixer, you'll want to stop and scrape the sides of the bowl a few times.
Add the eggs one at a time and beat well after each addition.
In a separate medium sized bowl, whisk together the cake flour, 1/4 cup all purpose flour, baking powder and salt.
With your mixer on low speed, gradually add the flour mixture to the butter mixture alternating with the milk while starting with the flour mixture and ending with the flour mixture.
Beat just until combined between each addition.
Beat in the vanilla extract.
Divide the batter evenly among 3 separate bowls.
In the first bowl, fold in a 1/2 cup of well stirred strawberry preserves and the remaining 1/4 cup all-purpose flour.
Combine the cocoa, 1/4 cup of boiling water and baking soda in a small bowl.
Fold the cocoa mixture into the second bowl of cake mixture.
In the third bowl of cake mixture, fold in a 1/2 cup of pistachio paste.
Spoon the cake batters into the prepared pans and smooth the tops with an offset spatula.
Bake in preheated oven for 20 to 25 minutes.
Test to see if its done by inserting a wooden skewer in the center of the cake. If it comes out clean then the cakes are ready.
Allow the cakes to cool in the pan for 10 minutes then invert onto a wire rack to cool completely.
ASSEMBLING THE CAKE LAYERS
Place the strawberry cake layer onto your serving platter and pipe a ring of vanilla buttercream all around the inside edge of the strawberry cake layer, creating a border.
Spread the remaining 1/2 cup strawberry preserves over the strawberry cake layer making sure to stay between borders.
Carefully place the chocolate cake layer over the strawberry layer and pipe a ring of vanilla buttercream around the inside edge, creating a border.
In a small bowl stir very well together 1/2 cup of the vanilla buttercream with the remaining pistachio paste and spread this over the chocolate layered cake while staying within the border.
Carefully top the pistachio cake layer over the chocolate cake layer.
Spread the remaining vanilla buttercream over the top and sides of the 3 layered cake. (I used a buttercream icing smoother to create the naked cake look)
Garnish with chopped pistachios and chocolate, strawberry, pistachio macaron cookies if desired.
Grind pistachios as fine as you can using a food processor or better yet a spice grinder if you have one.
Stir together the grind pistachios and honey in a small bowl.
Stir in 1/4 cup of water, 1 tablespoon at a time, until the paste has a consistency of peanut butter.
Pistachio paste can be made ahead and stored in an air tight container at room temperature up to one week.
Place the butter in a large bowl and beat at medium speed just until creamy.
Beat in the vanilla and the salt.
Reduce the speed to low and slowly add the confectioners sugar.
Increase the speed to medium and continue beating until smooth.
Beat in the milk one tablespoon at a time until the buttercream frosting reaches a spreadable consistency.