In a food processor run the pecans through until they become finely chopped. Add the remaining ingredients and pulse until a sandy texture. Press the mixture in the bottom and up the sides of a Springform pan. Bake for 8 minutes
In the bowl of a stand mixer, cream the cheese and sugar together until light and fluffy. Add the lemon juice, vanilla and eggs. Mix until well combined. Pour the mixture over the crust and bake for 40 minutes. Cool completely in the fridge before topping with the mousse layer.
For the mousse layer, melt the chocolate chips and butter in a medium sauce pan. In a separate bowl whisk together the egg yolks, sugar, coffee and vanilla. Stir a few tablespoons of chocolate in the egg mixture to bring up to temperature. Add the eggs into the sauce pan and stir over low until you reach 160 degrees. Place the pan in ice water to cool, about 2-3 minutes.
Whip the cream and gently fold into the chocolate. Smooth the mousse over the cheesecake and refrigerate until set.
Recipe by Friday is Cake Night at https://www.fridaycakenight.com/2014/05/chocolate-mousse-cheesecake/