Wash the baby spinach thoroughly and remove any thick stems. Peel the banana and slice it into smaller pieces so it blends easily. Measure the frozen strawberries, yogurt, milk, and flaxseeds so everything is ready before blending.

Pour the milk into the blender first to help the blades move smoothly. Add the Greek yogurt, spinach leaves, frozen strawberries, banana slices, and flaxseeds. Placing liquid ingredients at the bottom helps the blender process the frozen fruit and greens efficiently.

Blend on high speed for about 45–60 seconds until the smoothie becomes completely smooth and creamy. If the smoothie is too thick for your preference, add a small splash of milk and blend again briefly.

Pour the smoothie into a tall glass and serve immediately while cold and creamy. For extra presentation, garnish with a sliced strawberry or sprinkle a small pinch of flaxseeds on top.