Preheat your oven to 350°F (175°C). Grease a 9x5-inch loaf pan or line it with parchment paper for easy removal.
Dice 1-1/2 cup of apples into .25 inch cubes to go in the bread batter. Dice the remaining apple into 1/2 cup of .5" cubes to be used on top of the bread.In a medium bowl, toss the 1-1/2 cups of smaller chopped apples with 1/4 cup coconut sugar and 1/2 teaspoon cinnamon. Set aside to allow the apples to absorb the flavors. In a large mixing bowl, whisk together the 1/2 cup cane sugar, 1/4 cup light olive oil, 1/4 cup applesauce, 1 tablespoon apple cider vinegar, and 2 teaspoons vanilla extract until well combined. Add the 2 eggs, one at a time, whisking thoroughly after each addition.
Add the dry ingredients, including 2 cups oat flour, 2 teaspoons baking powder, 1/2 teaspoon baking soda, 1/2 teaspoon cinnamon, 1/4 teaspoon nutmeg, and 1/2 teaspoon salt and whisk until just combined. Gently fold in the 1-1/2 cups of smaller diced apples with a spatula.
In a small bowl, combine 2 tablespoons softened butter, 2 tablespoons cane sugar, 1/4 cup oat flour, 1/4 teaspoon cinnamon, and 1/4 teaspoon salt. Mix together with a fork until the mixture becomes crumbly.
Pour the bread batter into the prepared loaf pan, spreading it evenly.Sprinkle the oat crumble evenly over the top of the batter. Then add the 1/2 cup of larger diced apples and 2 tablespoons of pecans over the crumble. Bake the bread in the preheated oven for 45-55 minutes or until the top is lightly brown and a toothpick inserted into the center comes out clean. If the top starts to brown too quickly, cover it loosely with foil during the last 15 minutes of baking.Allow the bread to cool in the pan for 10-15 minutes, then transfer it to a wire rack to cool completely. Make the Glaze: In a small bowl, whisk together 1/2 cup powdered sugar, 1 tablespoon milk, and 1/2 teaspoon of vanilla until smooth. Adjust the consistency by adding more milk if needed. Once the bread has cooled, drizzle the glaze over the top. Let it set for a few minutes before slicing.