Make the nuts.  Preheat oven to 325 degrees F.  line a rimmed baking sheet with parchment.  Right on the pan, stir together almonds, vanilla, salt, oil, syrup, and espresso until well combined.  Bake, stirring every 5-10 minutes, for about 40 minutes, until the nuts are caramelized and the surrounding syrup is very thick.  Cool completely on the pan.  Nuts may be stored in an airtight container for up to 2 weeks.

Make the caramel.  In a medium saucepan, stir together the sugars, syrup, espresso, and water.  Cut the vanilla bean in half, scrape the seeds out, and stir those in along with the pod.  Turn the heat to medium, and cook, stirring occasionally, 5-10 minutes, until the mixture comes to a boil and cooks until thickened and darkened in color.  Remove from the heat and stir in the cream.  Place back over the heat and cook about 5 minutes more until once again thickened and a deep amber color.  Pour into a bowl and stir in the salt.  Cool to room temperature, then cover and refrigerate.  Caramel may be stored in an airtight container in the refrigerator for up to 1 week.

Make the cake.  Preheat oven to 350 degrees F.  Butter an 8 inch square pan and line the bottom with parchment.

In a large bowl, use a hand or stand mixer to beat the butter and sugar until light and fluffy.  Beat in the syrup, vanilla, and eggs, one at a time.  Stir in half the flour, followed by the bourbon.  Then add the other half of the flour and the baking soda.  Finish the batter by stirring in the milk.  Pour into the prepared pan and bake 25-30 minutes until risen, golden brown, and a toothpick inserted in the center comes out clean or with a few crumbs.  Cool completely in the pan.

When ready to assemble the cake, make the frosting.  In a large bowl, use a hand or stand mixer to beat the butter, almond butter, and caramel until well combined.  Slowly beat in cream until the mixture is fluffy and spreadable.

Remove the cake from the pan and carefully use a serrated knife to slice it in half horizontally.  Place the bottom half on the serving plate or cake stand of your choice.  Top with about 1 cup caramel, spreading into an even layer.  Sprinkle with ¾ cup chopped candied almonds and a drizzle of caramel on top.

Place the top half of the cake over the caramel and nuts.  Dollop frosting on the top and smooth on the top and over the sides.  Finish by garnishing with more of the almonds.  Cake may be stored in the refrigerator for up to 3 days.  Serve with an additional drizzle of caramel and sprinkle of nuts if desired.