Prepare the Homemade Chocolate Sauce: In a medium saucepan, whisk together the granulated sugar (100g, 1/2 cup) and unsweetened cocoa powder (30g, 1/3 cup) until well combined. This prevents cocoa lumps.

Gradually whisk in the heavy cream (120ml, 1/2 cup) until the mixture is smooth. Then, add the butter (15g, 1 tbsp) and place the saucepan over medium heat.

Stir the chocolate mixture constantly as it heats up. Bring it to a gentle simmer, but do not boil. Continue to stir for about 2-3 minutes until the sauce thickens slightly. The sauce should coat the back of a spoon.

Remove the saucepan from the heat. Stir in the vanilla extract (5ml, 1 tsp). Let the chocolate sauce cool slightly. It will thicken further as it cools.

Prepare the Fresh Whipped Cream: In a clean, chilled bowl, pour the heavy cream (250ml, 1 cup). Add the powdered sugar (30g, 1/4 cup) and vanilla extract (2.5ml, 1/2 tsp).

Using an electric mixer or a whisk, beat the cream mixture on medium-high speed. Start slowly to avoid splattering, then increase speed. Beat until stiff peaks form. This means when you lift the beaters, the cream holds its shape and the peaks stand straight up.

Assemble the Sundaes: Scoop generous portions of vanilla ice cream (about 250ml or 1 cup per serving) into two chilled serving bowls or glasses. Ensure the ice cream is firm enough to scoop.

Drizzle the slightly cooled homemade chocolate sauce (about 100ml or 3.5 fl oz per sundae) over the ice cream. Allow some sauce to cascade down the sides of the ice cream scoops.

Sprinkle the chopped nuts (about 25g or 1/4 cup per sundae) generously over the chocolate sauce and ice cream.

Top each sundae with a dollop of freshly whipped cream (about 100ml or 3.5 fl oz per sundae). You can pipe it for a fancier presentation or spoon it on.

Garnish each sundae with one maraschino cherry (2 per sundae) placed on top of the whipped cream.