Preheat the oven to 350 degrees F. Prepare and 8×8 inch pan with parchment paper.
In a medium sized bowl, mix the flour, ground flax seed, salt, baking powder, cocoa powder, sugar, chili powder, cinnamon, and cardamom. Stir until thoroughly combined.
In a double boiler (or heat-resistant bowl placed over a pan of simmering water), melt 1/2 cup of the chocolate chips. Stir in the plant milk and mix until completely smooth. Add the oil, agave, and vanilla. Mix well until everything is combined.
Stir the wet ingredients into the dry ingredients and stir until you have a thick batter. Do not overmix.
Stir in the remaining 1/2 cup chocolate chips and the walnuts.
Spread the batter in the prepared pan, filling in the edges and smoothing the top.
Bake 18-20 minutes or until the edges start to look dry and a toothpick inserted in the center comes out clean.
Allow the brownies to cool at least 15 minutes before cutting. Try not to eat them all in one sitting.
Store cooled brownies (if you have any left) in an airtight container.