Grease a 9" springform pan with butter.
Toast 1 cup of oats in a frying pan over medium heat till golden brown for 5-7 minutes, careful not to burn.
Add butter and graham cracker crumbs to the pan, stir to combine and turn out in the prepared springform pan.
Press the mixture into the pan with a spoon and leave it to set in the fridge for 1 hour.
Combine cream cheese, sugar, orange zest and juice of ½ an orange.
Scrape vanilla seeds out of the vanilla bean with a blade of a knife and add to the cheese filling along with a teaspoon of vanilla essence. Mix until smooth in a food processor or a stand mixer.
In a separate bowl whip your double cream until soft peaks form.
Fold half of whipped cream into the cheese mixture. Then gently fold in another half and pour it over the crumb base.
Chill in the fridge for 1 hour.
To prepare the topping-heat whipping cream in a small saucepan and take it off the heat right before it comes to a boil.
Pout hot cream over chopped chocolate, let it sit for 1 minute, then whisk the mixture until well blended.
Then blend in butter.
Spread chocolate topping over the cheesecake and put it back in the fridge for another hour.
Before serving run a knife along the edges of your springform to release the cheesecake.
Top with sliced blood oranges.