Preheat the Oven: Turn your oven on to 350 degrees Fahrenheit to get started.

Roast the Hazelnuts: Spread the hazelnuts on a baking tray and roast them for about 5 minutes. Let them cool off, then rub off the skins with your hands.

Grind the Hazelnuts: Put the cooled hazelnuts into a food processor and grind them until they're finely chopped.

Melt Nutella and Butter: In a microwave-safe bowl, mix Nutella and butter. Heat them in the microwave for about 30 seconds, or until the butter melts. Stir them together until they're smooth.

Mix in Powdered Sugar: Stir powdered sugar into your Nutella and butter mixture until it's fully combined.

Melt the Chocolate: Place chocolate chips in a separate bowl and microwave them for 2 minutes, pausing every 30 seconds to stir, until completely melted.

Prepare the Mold: Use a brush to coat your heart-shaped mold with the melted chocolate, making sure to cover all the spaces. Turn the mold upside down to let any excess chocolate drip out, then scrape the top clean.

Set the Chocolate: Put the chocolate-coated mold in the fridge for about 10 minutes or until it sets a bit.

Add Hazelnuts and Nutella Mixture: Sprinkle the ground hazelnuts into the chocolate shells. Next, fill each heart with the Nutella mixture, leaving a little space at the top for more chocolate.

Seal with Chocolate: Pour the rest of the melted chocolate over the filled molds to seal the hearts. Gently tap the mold on the counter to remove air bubbles and ensure the chocolate settles.

Clean the Edges: Scrape off any excess chocolate from the top of the mold.

Chill and Serve: Refrigerate the mold for at least 30 minutes or until the chocolate is firm. Once set, pop the Nutella Hearts out of the mold and they're ready to be enjoyed!