**Mix Dry Ingredients:**
In a large mixing bowl, combine the flour, oats, sunflower seeds, flaxseeds, chia seeds, brown sugar, salt, baking powder, and baking soda.
**Combine Wet Ingredients:**
In a separate bowl, mix the buttermilk, egg, and melted butter.
**Mix the Dough:**
Gradually add the wet ingredients to the dry ingredients, stirring until just combined. The dough will be thick and sticky.
**Prepare the Pan:**
Line a loaf pan with parchment paper and lightly grease it. Transfer the dough into the pan, smoothing the top with a spatula. Sprinkle extra oats on top for decoration.
**Bake:**
Preheat your oven to 375°F (190°C). Bake the bread for 45–50 minutes, or until a toothpick inserted into the center comes out clean and the top is golden brown.
**Cool:**
Allow the bread to cool in the pan for 10 minutes, then transfer it to a wire rack to cool completely before slicing.