Preheat oven to 350°F and prepare muffin tin by spraying with nonstick spray.
In a large bowl, stir together dry ingredients.
1 3/4 cups white whole wheat flour, 2 teaspoons baking powder, 1 teaspoon baking soda, 1/2 teaspoon salt
In the blender, add wet ingredients, then blend on high for 30-60 seconds until blended smooth.
1/2 cup Greek yogurt, 1/2 cup milk, 1/2 cup light brown sugar, 1/4 cup butter, 2 eggs, 2 teaspoons vanilla extract, 2 cups fresh spinach
Pour wet ingredients into the dry ingredients, then carefully stir until just combined (don't overmix!).
Fold in the mini chocolate chips.
1/2 cup mini chocolate chips
Scoop muffin batter into the prepared muffin tin. Top with the regular-sized chocolate chips, placing them as a placeholder for where you'll want the eyeball sprinkles to go.
2 tablespoons chocolate chips
Bake for 18-20 minutes on the center or bottom rack. Muffins should be slightly golden brown. If you gently press the top of a muffin it should quickly spring back when the muffins are done (but not stay pressed down).
Carefully place the eyeball sprinkles on the chocolate chip placeholders, gently pressing them in.