Preheat the oven to 350º F. Line an 8-inch square baking dish with parchment paper. If you don't have parchment paper, just grease the baking dish and dust with flour.
In a large bowl mix together the oil, almond milk, and cocoa powder for the brownies.
Add in the sugar, egg, and vanilla, and mix until well combined.
Add the flour and salt. Mix until just combined
Pour the brownie batter into the prepared pan and make sure it's spread evenly.
Bake for 25-30 minutes, until a tester comes out mostly clean.
Remove the brownies from the oven and allow to cool completely.
While the brownies bake or cool, add all the frosting ingredients to a bowl and beat together until the frosting is the desired consistency. Adjust the sugar if the frosting isn't sweet enough, and add more almond milk if the frosting is too thick.
When the brownies are cooled, frost them and enjoy.
Notes
Store leftovers in an airtight container at room temperature for 4 days or in the fridge for 1 week.
Leftovers can also be stored in two layers of airtight bags in the freezer for 3 months.
To make the brownies vegan, replace the egg with a flax egg.