For the ice cream: Bring the milk, cream, sugar, honey and milk powder to a boil. Stir occasionally to dissolve the milk powder, so it doesn't burn at the bottom of the pot.
Pour over the dark chocolate and whisk together until all the chocolate is melted. Using an immersion blender, mix until it's smooth and even. Chill the base over an ice bath until cold, and process in ice cream machine according to manufacturer's instructions.
For the cake: Preheat the oven to 350 degrees F. Grease and flour two 8-inch round cake pans.
Whisk together the coffee, mayonnaise, sugar and vanilla paste, and whip until fluffy. Sift together the flour, baking soda, salt and cocoa powder, and incorporate until just barely mixed.
Pour into the prepared cake pans. Bake until toothpick inserted comes out clean, 25 to 30 minutes. Cool 5 minutes in the pans, and then turn upside down on wire racks until completely cool.
Cut into 60 to 80 crouton-size cubes (any remaining cake can be wrapped and kept frozen).
For the whipped cream: Whip the cream, sugar and vanilla paste until it holds a firm peak and can be spooned.
To assemble: Scoop 2 scoops of the chocolate ice cream into a dish, and top with 6 to 8 pieces of chocolate cake croutons.
Drizzle 2 tablespoons citrus-olive oil directly over the ice cream. When it hits the cold ice cream it will thicken like a sauce. Top with the whipped cream and a generous pinch of sea salt.