Was the capsicums, carefully chop off their lids and scoop out the insides.
Place them in a bowl of boiling water for 3 minutes to soften them and then drain them and put them in a baking dish.
Pre-heat the oven to 180C fan-forced.
Spray a large, non-stick pan with a little oil and cook the onions, stirring, until softened.
Add the garlic, ginger, mushrooms, squash and beans and stir it all together. Cook, stirring, for 3 minutes then add the oyster sauce and sesame seeds.
Cook for another 2 minutes.
Divide the mixture between the hollowed-out capsicums and then put the lids on them.
Pour 2cm of water into the baking dish and cover the capsicums with aluminum foil.
Bake for 40 minutes.
Leave them to sit for a couple of minutes before serving.