In a mixing bowl, mix together condensed milk, oil, hot milk, lemon juice and vanilla.
Place a sieve over the liquid mixture and add in the flour, instant coffee, baking powder, baking soda and salt. Sift and mix well till just combined; add ground walnuts.
Pour the batter into a baking sheet lined with parchment paper. Bake in an oven preheated to
180°C for 12-15 minutes or till the top is golden.Remove and let it cool completely.

Heat together sugar, water and sea salt till it turns into golden caramel. In the meanwhile, heat the heavy cream just till bubbles start to appear around the edges.
Pour the hot cream into the caramel continuously stirring with one hand.
Cool the mixture completely chill it in fridge
Whip the caramel cream till stiff peaks form.

Mix everything together using your fingertips till it resembles the texture of breaderumbs.
Sprinkle the crumble on a baking pan and bake for 5-7 minutes in an oven ;cool completely before using for garnish.

Assembly ~
Using a small round cutter, cut out the espresso walnut cake.
Pipe out the salted caramel whipped cream and sandwich cake layers.
Pipe out a swirl of the cream on top, sprinkle the chocolate crumble over it