Whisk together honey, maple syrup, olive oil and water until the honey and syrup have dissolved, then sprinkle active dry yeast across the top. Let sit for 10-15 minutes.
In a large mixing bowl, whisk together flour, oats, dark brown sugar, salt and cinnamon and let sit for 10 minutes.
Pour in the yeast mixture and mix everything together until no dry flour patches remain. The dough will be wet and sticky. Cover and let rise until the dough has doubled in volume, about 1 to 1.5 hours hours. If you don’t intend to bake it right away, at this point you can place the bowl in the refrigerator, covered tightly with plastic wrap, where it will keep for up to 24 hours.
Once you’re ready to bake, butter a 9x5-inch loaf pan and prepare your dough for its second rise. Sprinkle 1 tablespoon flour across the top of the dough. Using your hand or a flexible dough scraper, pull the dough away from the sides of the bowl, turning the bowl with your left hand until the dough begins to take the shape of a loaf. Lift the dough out of the bowl, turn it over and place it smooth side down onto a lightly floured surface, taking care not to completely deflate it. Flour your hands again and take one end and lift and fold 1/3 of the dough into the centre as if you were folding a letter. Repeat with the other end, then turn and place loaf seam side down. Gently pat it into an oblong log shape that matches the length of your pan.
Lift the dough carefully and place it smooth-side-up into the prepared loaf pan. Brush the top surface of the dough lightly with 1 teaspoon of pure maple syrup. Evenly scatter the remaining ¼ cup of rolled oats across the top, pressing down very gently so they adhere to the maple glaze. Cover loosely and let rise a second time for 30 to 45 minutes, just until the dough crowns the rim of the pan.
Position a rack to the centre of the oven and preheat to 350ºF (177ºC). Bake for 38 to 42 minutes (40 minutes is usually the sweet spot) until the top is a rich, golden-brown colour and it sounds hollow when you tap on the top.
Remove the pan from the oven and immediately brush the top of the loaf lightly with melted butter for a soft finish. Sprinkle with flaky salt and let the loaf sit in the pan for 10 minutes. Carefully turn it out onto a wire cooling rack and allow the bread to cool completely for at least 1 hour before slicing.