Preheat the oven to 375°F (190°C) and lightly grease a 12-cup muffin pan.
In a large bowl, mash 2 ripe bananas until mostly smooth.
Add 1 cup Greek yogurt, ¼ cup milk, ¼ cup honey, 1 large egg, 1 teaspoon vanilla extract, and the zest of 1 lemon. Whisk until smooth.
Stir in 1½ cups rolled oats and 1 teaspoon baking powder until no dry bits remain.
Gently fold in 1 cup blueberries.
Spoon the mixture evenly into the muffin cups, filling them to the top.
(Optional) Sprinkle ¼ cup slivered almonds on top for crunch.
Bake for about 25–27 minutes at 375°F (190°C) until set and lightly golden.
Let cool in the pan for 20–30 minutes before removing.
