Line a 9″ square pan with a sheet of wax paper, make sure there’s overhang on two sides (you’ll use it to easily remove the bars later). Grease exposed sides with butter or oil; set aside.

Mix together oats, puffed millet and coconut (if using) in a large, heatproof bowl (4-quart); set aside. In a small saucepan (2-quart), combine oil, agave and brown sugar. Set over high heat and bring to a boil, stirring constantly; cook until sugar is dissolved and mixture is syrupy, about 30 seconds. Remove from heat and whisk in flaxseed meal, stir until evenly distributed. Whisk in peanut butter, vanilla extract and salt, stir until smooth.

Pour syrup mixture over oats (it won’t really look like enough, but it will be!), stir with a spoon until mixture is cool enough to handle. Use super clean hands to continue to mix/knead until everything is evenly coated. Mix in peanut butter chips. Pour mixture into prepared pan and pack down to make an even layer (about ¹⁄₂” thick). Cover and refrigerate for about 1 hour to set.

Once set, use wax paper overhang to lift granola bar block out of the pan. Cut into 12 bars (about 1 ¹⁄₂” x 4 ¹⁄₂” each). Wrap each bar in wax paper or plastic wrap, and transfer to a storage bag or airtight container. Store in fridge or freezer, allowing bars to come to room temperature before enjoying!