Designed as a true alternate build, this MOC uses only parts from the donor LEGO set or sets, including the spare pieces included in the box. All PDF instruction sales are final and non refundable.

The castle is 22.4 cm wide, 16.0 cm deep, 15.6 cm tall Or 8.8 inches wide, 6.3 inches deep, 6.1 inches tall.

When I first saw the new LEGO 40975 Mini Hogwarts Castle announced, I immediately wondered what could be done with two copies of the set. The original is an impressively compact interpretation of Hogwarts, packing the Great Hall, Main Tower, East Wing and Astronomy Tower into a surprisingly small model. With a second set available, there was an opportunity to take the design much further.

My main goal was to create a less cramped version of Hogwarts while keeping the distinctive microscale style of the original. The additional parts allowed me to expand the towers, buildings and courtyards while maintaining the compact appearance that makes the original so appealing.

One of the biggest changes is the overall footprint. The Expanded Edition measures 22.4 cm (8.8 in) wide, 16 cm (6.3 in) deep and 15.6 cm (6.1 in) tall, making it 76% larger in footprint than the original castle, which measures 17 cm (6.5 in) wide, 12 cm (5 in) deep and 14 cm (5.5 in) high.

I particularly enjoyed working on the East Wing, Long Gallery and North Courtyard. At this scale, even a few studs can make a surprising difference, allowing me to create taller towers and give the architecture more depth. I also added the Whomping Willow to the grounds using a broom end.

The Great Hall and Grand Staircase Tower remain the centrepiece. The Great Hall is now 5 studs long, with a prominent central spire flanked by a smaller spire at each end. I also adjusted the spacing between the structures to better represent the original architecture.

Across the ravine behind the Quadrangle now stands the Clock Tower, the standout feature of the West Wing. Adding it completes the major architectural features of the castle.

The hidden features from the original model are also retained and enlarged. The Chamber of Secrets remains beneath the courtyard, while the Mirror of Erised can still be found within the castle. However, because the courtyard is now larger than the original 6 × 10 plate, it can no longer be lifted to reveal the entire Chamber of Secrets.

I wanted the Expanded Edition to feel like a natural evolution of the original rather than simply two castles joined together. Considerable time went into rearranging structures, adjusting proportions and integrating the two sets into one cohesive model.

I also used the remaining pieces to create a Gothic Cathedral to accompany the castle. The cathedral follows a Latin cross plan, with twin towers at the west end and a larger main tower above the transept. At the eastern end, a rounded apse is supported by flying buttresses, creating a distinctive Gothic silhouette from the leftover pieces.

The final model keeps the charm of the original Mini Hogwarts Castle while giving it a much greater presence on display. It is still unmistakably a microscale Hogwarts, but the extra size allows the individual architectural features to breathe and creates a more imposing silhouette.