1. Place the hazelnuts in the bowl fitted with the ultrablade knife. Mix at speed 12 for 2 minutes, gradually adding oil through lid. Scrape down the sides of the bowl once or twice during mixing. Replace the ultrablade knife with the mixer.
2. Add the butter and mix at speed 3 at 160°F for 4 minutes or until butter is melted.
3. Add the chocolate and melt at speed 3 at 110°F for 5-6 minutes or until chocolate is melted. Add the condensed milk and mix at speed 7 for 30 seconds.
4. Place the mixture in a dish and refrigerate until ready to use.