No-bake, no-egg coffee mousse cake with chocolate ganache

The coffee mousse cake recipe (round pan size 15cm) : 1 cup = 236ml

The base
150g chocolate chip cookies (finely grounded)
30g g melted butter (2 tbsp)

The mousse
100g mascarpone cheese (1/4 cup)
1 tbsp (8g) gelatine powder (or 5g gelatine sheet)
60ml cold water to bloom gelatine (2 tbsp)
50g sweetened condensed milk (3 tbsp)
1/2 tsp vanilla extract (5ml)
350ml heavy cream (1.5 cup)
30g sugar (2.5 tbsp)
1 tbsp (5 g) espresso powder

Chocolate ganache
125g dark chocolate (3/4 cup)
125g heavy cream (1/2 cup)
25g vegetable oil (2 tbsp)

20 - 30g melted chocolate and cocoa nibs for garnish