In a food processor, whiz the biscuits and pecans until fine. Mix in 50g melted butter and press onto a well greased spring-form cake tin. Bake this in the oven for 5 minutes at 190 degrees. Remove from the oven to cool and turn the temperature down to 180 degrees.
In a large bowl using an electric hand mixer or in a food mixer blend the cream cheese with the sugar until light and fluffy.
One at a time, add the eggs/egg yolks, beating gently but well between each addition.
Add the vanilla essence.
Melt the white chocolate, let cool and slowly add to the cream-cheese mixture ensuring it is incorporated well into the mix.
Gently fold in the raspberries (or alternatively, you can place the raspberries on the biscuit base and then pour the filling mixture on top of this).
Bake in the oven for approx 45 minutes - when the sides have come away from the tin but the inside is still slightly wobbly you know it is cooked. Remove from the oven and let cool. This might take some time. It's best to let it set overnight in a fridge but it should cool to room temperature within a few hours.
Spread a thin layer of raspberry jam over the top of the cooled cheesecake. Place the remaining fresh raspberries on top and dust with icing sugar. Alternatively, you can decorate with freshly whipped cream and white chocolate shavings.