Preheat oven to 180°C. Slice pumpkin into 1cm slices. Brush lightly with a little extra virgin olive oil oil (optional) and bake in the oven until lightly coloured, 40-50 min.
Meanwhile, to a medium bowl add mushrooms, bok choy, coriander, spring onion, ginger and soy sauce. Stir to combine.
Place frying pan onto medium high heat and heat up the sesame oil. Add mushroom and greens mixture and cook for 4 min. Set aside in bowl.
Once pumpkin is lightly browned on the edges, mash and add to the mushroom and greens.
When the mixture is cool enough to handle, scoop one large teaspoon of vege mixture into the centre of a dumpling wrapper. Dip a finger in water ands wet the edges of the wrapper. Bring the two opposite sides together and press together. (For a fancy fold, YouTube some cool folding techniques.)
Oil steamer if needed or line with baking paper. Be sure to leave space for steam to come through if using baking paper. Place dumplings into a steamer in a single layer, not touching. With the steamer over the top of a large pot of boiling water, steam for 5 min in batches.
Finish with a sprinkling of toasted sesame seeds and a squeeze of lemon juice over the dumplings (optional but not really). Serve on their own, with a dipping sauce, in a broth or with a crunchy slaw.