Preheat the oven to 350ºF and line a 9 x 9 baking pan with parchment paper.
Make the flax eggs by stirring the ground flax and water in a small bowl. Set aside to thicken.
In a large microwave-safe bowl, melt the vegan butter. Then whisk the butter with the granulated sugar and the brown sugar until creamed. Add the flax eggs and peppermint and whisk until evenly combined.
Over the same large bowl, sift in the flour, cocoa powder and salt. Add the salt and stir with a large wooden spoon until just combined, do not overmix.
Fold in the chocolate chips. Pour the batter into the prepared pan and smooth out the top.
Bake in the preheated oven for 40-45 minutes, until the middle of the brownies no longer jiggles and is just set.
Remove from the oven, sprinkle the crushed peppermint on top, and allow to cool in the pan for 15 minutes.
Then pull the brownies out, using the parchment paper and let cool on a wire rack for another 15-30 minutes before slicing and serving.