Preheat your oven to 350°.
Melt butter in a saucepan. Use a pastry brush to grease the inside of a 6x9 bread loaf pan. Set remaining butter off to the side.
In a large bowl, measure and add flours, oats, baking soda and salt. Whisk to combine. Use a spatula to create a well in the middle of the dry ingredients. Set off tot he side for a moment.
In a separate mixing bowl, measure and add buttermilk and eggs. Whisk to combine and pour into the well of the dry ingredients. Use a spatula to mix until just about combined. Pour in the remaining melted butter and stir to incorporate.
Transfer the batter to the prepared pan and give it a few firm taps on the counter to settle and remove any air pockets. Smooth the top of the batter with the spatula. Sprinkle with a few pinches of oats.
Bake on the middle rack of your preheated oven for 40 minutes. Remove and run a dull knife around the edge of the bread to loosen. Carefully, using oven mitts, invert the bread onto a rimmed sheet pan and flip it right side up. Bake for 10 more minutes.
Let cool before slicing and serving with softened salted butter.
Store in an air-tight container or large re-sealable bag at room temperature for 4 to 5 days.
