Melt 200 grams of white chocolate using the double boiler method.

Put the melted chocolate in a piping bag.

Take a silicone mold and fill it with a thin layer of melted white chocolate. Place the in the refrigerator until the chocolate has hardened.

Grind the walnuts in a food processor.

Finely grind the chocolate waffle cookies in a food processor.

Finely grind the Maria biscuits in a food processor.

Put the walnuts, chocolate waffle cookies, Maria biscuits, and condensed milk in a large bowl. Mix well.

Remove the silicone mold with the hardened white chocolate from the refrigerator. Distribute about 20 grams of the cookie mixture into each mold and press it down with a glass. Make sure to place a piece of paper under the glass to prevent sticking.

Melt the remaining 200 grams of white chocolate using the double boiler method. Pour this over the cookie mixture and tap the mold a few times on your work surface to ensure the white chocolate is evenly distributed.

Melt the dark chocolate using the double boiler method and transfer it to a piping bag.

Pipe lines of dark chocolate over the cookies. Use a toothpick to create a decorative pattern. Let the chocolate fully harden before removing from the silicone mold.