Peel and chop potatoes into 3cm squares and cook in salted water until just done. Allow to cool.
Blanch spinach and refresh in iced water or under running tap. Squeeze until dry.
Slice leeks into 2cm circles.
Melt butter and sugar in a 26cm pan. Add leeks and water and gently fry for a few minutes on each side to caramelise. Allow to cool.
Dressing
Mix all dressing ingredients together.
Gently fold through potatoes.
Line a 23cm cake tin or glass bowl with cling film and then cover bottom and sides with spinach, potatoes, leeks and red peppers. (It is served upside down so arrange as desired.)
Continue to layer ingredients until finished. Cover and press gently to compact.
This is best turned out after it has been refrigerated for a few hours, allowing it to set.