Place the dark chocolate, milk chocolate and white chocolate into separate microwave-safe bowls.
Place each bowl in the microwave and heat for short periods of 30 seconds at a time, stirring in between, until the chocolate is smooth and melted.
Divide the melted white chocolate between 3 bowls and add 2-3 drops of Dr. Oetker Extra Strong Colour Gels to two of the bowls. Stir, and add more drops for a stronger colour.
Take a large baking tray and line it with baking parchment. Gradually spoon on the different chocolates one tablespoon at a time. Once all the chocolate is on the tray, take a cocktail stick and gently swirl it through the chocolate to create a marbled effect. Gently tip the tray from side to side to ensure the chocolate has set over an even surface space.
Decorate with the chocolate eggs and sprinkles. Leave to set in a cool place, or in the fridge, then break up to serve.