Crush tennis biscuit in a bowl.

Melt a half a cup of butter save other half for later.

Add melted butter to crushed biscuits and mix with a fork until combined

Press down in dish/pan of your choice

In a small pot melt butter, chocolate, salt and vanilla essence

Once melted, Add in milk and geletine and continue stiring

Stir until mixture becomes thick

Once thick, pour onto biscuit base

Smooth out and place in the fridge until set