Homemade Chocolate Swiss Roll

Vanilla Whipped Cream filling:
1 cup chilled whipping cream
3-4 tbsp sugar
1 tsp vanilla
For chocolate ganache glaze:
1/2 cup whipping cream
2-3 tbsp Nutella or melted chocolate
1-tbs cocoa powder
1/2 tbsp sugar(optional)
1/2 tbsp corn flour + 1-2 tbsp water
1 Tbsp butter