Grease and line a 15cm loose-bottomed cake tin with baking parchment. Whiz the biscuits in a food processor or crush with a rolling pin until they are fine crumbs, then mix with the melted butter. Pour into the tin and use the back of a spoon to press the mixture down evenly over the base. Put in the fridge to set while you make the filling.
Put the soft cheese, condensed milk, lemon juice, orange zest and cream in a bowl. Beat together with an electric hand whisk until thickened. Pour into the tin over the biscuit base.
Put 50g of the raspberries in a bowl and lightly crush with a fork. Spoon on top of the filling and, using a knife or a skewer, gently draw the crushed raspberries through the creamy cheesecake mix, creating a swirl effect. Chill in the fridge for 3-4 hours until set.
Pile the remaining raspberries on top of the cheesecake, sift the icing sugar over the top and slice to serve.