Combine oat flakes, buckwheat, walnuts, sunflower seeds, salt and cinnamon in a bowl and mix. Now mash the banana with a fork until creamy. Combine the mashed banana, honey, vanilla and melted coconut oil with the oatmeal/nut mixture by using a kitchen spatula. You can melt the coconut oil either in a water bath, in a heat-resistant container in the oven or in the microwave. Sometimes I also heat the honey because it is best mixed in a completely liquid state.