Stir together all topping ingredients with a fork in a medium sized bowl. Reserve. If refrigerating overnight, do not pack.
Make Muffins
Preheat oven to 350°F (Convection oven: 325°F). Line muffin pans with paper baking cups.
Mix eggs with stand mixer fitted with a whisk attachment about 1-2 minutes until thick and frothy. Drizzle in oil while whisking until creamy. Add sugar and beat for an additional two minutes. Whisk in vanilla, vinegar, baking soda, salt and sour cream. Remove from stand mixer and add in flour by hand using a spatula. (Batter will be slightly lumpy.) Fold in blueberries.
Fill muffin cups 3/4 full. Sprinkle the crumble evenly over the top of the muffins.
Bake for 15-22 minutes until a toothpick comes out clean from the center of a muffin. Cool 5 minutes in pan then remove to a rack to cool completely.
Store in an airtight container for up to 3 days or freeze for up to one month.
Notes
Substitute two-three bananas for blueberries, if desired.