Prepare the base mixture: In a medium mixing bowl or a large jar with a lid, combine the rolled oats, milk, and Greek yogurt. Stir well to create a smooth and evenly blended base. Make sure the oats are fully submerged in the liquid to allow proper softening overnight.

Add flavor ingredients: Add the grated carrot, maple syrup (or honey), cinnamon, nutmeg, ginger, vanilla extract, chia seeds, and a pinch of salt. Mix thoroughly so that all the spices and ingredients are evenly distributed throughout the mixture. This step helps develop the classic carrot cake flavor.

Incorporate mix-ins: If using, fold in raisins and chopped nuts. Stir gently to ensure they are evenly spread without clumping at the bottom.

Refrigerate: Cover the bowl or seal the jar with a lid. Place it in the refrigerator and let it chill for at least 4 hours, though overnight is recommended for the best texture and flavor. During this time, the oats and chia seeds will absorb the liquid and thicken into a creamy consistency.

Check and adjust: Before serving, remove from the refrigerator and give the oats a good stir. If the mixture is too thick, add a splash of milk to loosen it to your preferred consistency. Taste and adjust sweetness if needed by adding a little more maple syrup or honey.

Serve: Spoon the overnight oats into bowls or enjoy directly from the jar. You can top with extra grated carrot, a sprinkle of cinnamon, or additional nuts for texture and presentation. Serve chilled for a refreshing and hearty breakfast.