Preheat oven to 350F and grease a 9x9 square baking pan. Line with parchment paper, with some overhanging the sides for easy release. Grease parchment.
In a medium bowl, whisk together chia seed meal, sweetener, baking soda and salt.
In a large saucepan over low heat, melt butter and chocolate together, whisking until smooth.
Whisk in eggs (mixture may seize), then whisk in coffee. Stir in chia seed mixture until well combined. Stir in chocolate chunks.
Spread batter in prepared pan and bake 15 to 16 minutes for a fudgier consistency or 18 to 20 for a cakier consistency.
Remove and let cool completely in pan.
Remove brownies from pan by grasping the overhanging parchment and lifting carefully. Cut into 16 squares.