Line an 8x8-inch square baking pan with parchment paper, allowing edges to overhang for easy removal. This step prevents sticking and makes portioning the final no bake oatmeal bars effortless.

In a medium saucepan over low heat, combine 1/2 cup unsalted butter, 1 cup natural peanut butter, and 3/4 cup honey. Stir constantly for 3-4 minutes until the mixture melts completely and becomes smooth and glossy throughout.

Remove from heat and fold in 2 cups old-fashioned oats, 1/2 cup chopped walnuts, 1/4 cup ground flaxseed, and 1/2 cup shredded coconut. Mix thoroughly until every oat is coated and the no bake base feels uniform and well-combined.

Press the mixture firmly into your prepared pan using the bottom of a measuring cup or spatula. Compress thoroughly so the bars hold together; this takes about 2 minutes but ensures proper structure when sliced later.

In a small bowl, whisk together 1 cup semi-sweet chocolate chips, 1/4 cup cocoa powder, 1 tsp vanilla extract, 2 tbsp maple syrup, and 1/4 tsp sea salt. Heat this chocolate topping in 30-second microwave intervals, stirring between each, until completely melted and smooth (typically 90 seconds total).

Pour the chocolate mixture evenly over the pressed oatmeal layer, spreading gently with an offset spatula or the back of a spoon. Work quickly so the chocolate doesn't set before you achieve an even coating across the surface.

Transfer the pan to your refrigerator and chill for at least 2 hours until the chocolate layer sets completely and the bars firm up enough for cutting. The cozy no bake oatmeal bars will reach perfect slicing consistency at this point.

Remove from the pan using the parchment overhang, place on a cutting board, and slice into 12 equal squares. Serve immediately or store in layers separated by parchment for later enjoyment.