Preheat oven to 425 degrees. Line a standard size muffin tin with liners, set aside
In the bowl of a stand mixer fitted with the paddle attachment, add the butter and canola oil. Add sugars, then mix on low until combined, about 1 minute.
With mixing speed on low, add eggs one at a time, then vanilla. Mix just until combined.
In a separate mixing bowl, whisk together the flour, oats, baking powder, cinnamon, and salt. With mixing speed on low, gradually add the the dry ingredients(along with the apples if using) and mix just until combined.
Divide the batter between the liners.
To make the topping, combine all the ingredients in a small mixing bowl and toss until moist. Sprinkle over top of the muffins.
Place in the oven and bake for 8 minutes, then reduce oven temperature to 350 degrees and bake for 12 additional minutes.
Remove from the oven and allow to cool in the pan for 5 minutes before removing and transferring to a wire rack to cool completely.