Preheat oven to 350 F and line 8 muffin tins
Sift all dry ingredients into a small bowl and set aside
In a large bowl or stand mixer whip together white sugar, brown sugar, eggs, rum, vanilla bean paste, espresso powder and greek yogurt until smooth and creamy (about 5 minutes)
Add in olive oil and 3 mashed up VERY RIPE bananas
Add dry ingredients to wet ingredients and mix just until combined
Add in chocolate chips
Take about 1 cup of the muffin batter and place in a separate bowl. Add coco powder to this small bowl and mix until combined
Separate the muffin batter evenly between 8 muffin liners, top each muffin with a dollop of the chocolate muffin batter and swirl with a toothpick
Dust each muffin with sugar and bake for 25-35 minutes dependent on your oven
Once out of the oven sprinkle with flakey sea salt and enjoy
