Khandro Nyingtik (Heart Essence of the Dakinis) is part of one of the most famous collections of Dzogchen texts, the Nyingtik Yabshi. The collection includes the Khandro Nyingtik by Padmasambhava, the Vima Nyingtik by Vimalamitra, the Khandro Yangtik and Vima Yangtik (Longchenpa's (1308-1364) commentaries on these respectively), along with Zambo Yangtik (his additional commentary on the four texts), all collectively referred to as the Nyingtik Yabshi.  

The Precious Golden Garland of Instructions  "It contains almost exclusive original prose by Longchenpa himself. Through the treasure of Longchenpa’s own realization, the key points of Dzogchen pith instructions are revealed in all their majestic glory. This text specifically covers the most practical aspects of the path. This marvelous commentary goes through the common preliminaries from the Dzogchen perspective, the uncommon Dzogchen preliminaries of separation (ru shan) and such, the introduction and practice of cutting through (khregs chod), extensive guidance on the introduction and practice of direct transcendence (thod rgal), navigating death, the bardos, and rebirth if necessary. Essentially, with proper guidance, these instructions provide the entire scope of means to attain complete enlightenment and the rainbow body of the great transfer." - Eric Fry-Miller, translator. The text is available from