Mix wet ingredients (peanut butter, coconut oil, honey, vanilla) + cinnamon in a medium saucepan over low heat. Stir occasionally until smooth.
Remove smooth mixture from heat + stir in dry ingredients (flaxseed meal, chia seeds + rolled oats). Fold in chopped nuts + shredded coconut.
Choose a smaller pan size (like 9x9 or 8x4) + line with parchment paper.
Pour mixture on top of parchment paper, spreading the mixture out evenly + firmly. Press any desired extra chopped nuts on top.
Place dark chocolate chips + 1/2 teaspoon of coconut oil in a small pan on medium-low on stovetop. Stir until completely melted, then quickly drizzle melted chocolate mixture over bars diagonally.
Set bars in refrigerator for 25-minutes, then the freezer for another 10-minutes until the mixture has hardened.
Remove bars from freezer, cut into skinny granola bar rectangles (about 12) + store in an airtight container (in bulk or individually wrapped) in the fridge for up to 7 days.