Melt butter, add 125 ml of water and honey and bring to a boil. Peel and quarter the apple and remove the core. Grate the pulp. Wash the orange, zest the peel and squeeze out the juice. Carefully mix the rolled oats, coconut flakes, hazelnuts, flaxseed, sesame seeds, grated apple, orange zest and orange juice into the honey batter.
Lay baking paper onto a baking sheet. Spread the batter about 1 cm thick onto the baking paper in a 20 x 30 cm rectangle and press down well to set. Mark cutting lines for the bars. (2 cm x 10 cm). Bake the bars in a preheated oven (electric: 200°C/ Gas: level 3) 15–20 minutes, then carefully cut out the bars, following your markings, and let them cool.
Chop and melt the chocolate. Frost the bars with it.