How to Make It
Preheat the oven to 350°. Spread the coffee beans on a baking sheet and toast for 10 minutes, until fragrant. Transfer to a large bowl. Stir in the heavy cream and milk, cover and let steep in the refrigerator overnight.
Strain the coffee cream through a fine sieve, pressing on the solids; you should have 2 cups. In a large saucepan, cook the sugar over moderate heat, stirring occasionally, until a light amber caramel forms, about 5 minutes. Slowly add the coffee cream; be careful, as it will boil vigorously. Add the corn syrup, espresso and sea salt and bring to a simmer; the caramel will harden but will dissolve as it simmers. Cook over moderately low heat, stirring, until a candy thermometer inserted in the caramel jam registers 210°, about 12 minutes. Carefully transfer the jam to a blender and puree until smooth and shiny. Scrape into a medium bowl and let cool to room temperature.
In a medium bowl, whisk the all-purpose flour with the almond flour, sugar, cocoa powder and sea salt. Using your fingers, rub in the butter until coarse crumbs form. Spread the crumbs in an even layer on a parchment paper–lined baking sheet and refrigerate until firm, about 1 hour.
Preheat the oven to 350°. Bake the crumble for about 18 minutes, until golden. Transfer to a rack to cool completely.
Spread some coffee-caramel jam on the toasts. Sprinkle the chocolate crumbles on one half of each toast; press gently to help them adhere.