Step 1: Prepare
Preheat oven to 350°F (175°C). Line 8x8-inch baking pan with parchment paper, leaving 2-inch overhang on two sides. Lightly grease parchment.
Step 2: Melt Fat
In small saucepan over low heat, melt coconut oil or butter. Remove from heat and cool 2 minutes.
Step 3: Mix Wet Ingredients
In large bowl, whisk together melted oil, honey, brown sugar, vanilla, and salt until smooth.
Step 4: Combine Dry Ingredients
In separate bowl, mix oats, cinnamon, and chosen add-ins (nuts, seeds, protein powder). Toss to distribute evenly.
Step 5: Combine Everything
Pour wet mixture over dry ingredients. Fold with spatula until every oat is coated. Mixture should be sticky and hold together when pressed.
Step 6: Press Into Pan
Transfer mixture to prepared pan. Use back of spatula or damp hands to press firmly into even layer. Compress well for bars that hold together.
Step 7: Bake
Bake 22-25 minutes until edges are golden brown and center looks set. Don't overbake—center may appear slightly soft but will firm during cooling.
Step 8: Cool Completely
Let cool in pan at least 1-2 hours. Use parchment overhang to lift entire block from pan.
Step 9: Cut
Cut into 12 bars using sharp knife with firm downward pressure. Wipe knife clean between cuts.