Add the pitted and peeled avocados, cocoa powder, syrup, vanilla extract, sea salt, orange zest, and plant-based milk to a high-speed blender or food processor.
Blend on high until the mixture is completely smooth and creamy. You may need to stop and scrape down the sides of the container once or twice to ensure everything is fully incorporated.
Serve immediately with fresh strawberries for dipping, or chill in the refrigerator for 30 minutes for a firmer texture.
Adjust sweetness to your taste.
After blending, give the mousse a taste and add a little more syrup or a tablespoon of maple syrup if you prefer it sweeter.