Start with Greek yogurt frosting. Line a colander with cheesecloth folded 4 times and place over a smaller bowl. Add yogurt and let drain in the fridge for 2-4 hours, up to 6 hours is OK.
Bake bars. Preheat oven to 375 degrees F, line 9 x 13 baking dish with unbleached parchment paper and spray with cooking spray. Set aside.
In a large bowl, add eggs, milk, applesauce, maple syrup, oil, vanilla extract, cinnamon, nutmeg, baking powder, baking soda and salt; whisk well to combine. Add carrots, oats, flour, chia, raisins, walnuts, and pumpkin seeds; using spatula mix very well.
Transfer mixture to previously prepared baking dish, level with spatula and then press into the dish. Bake for 30 minutes, remove from the oven and let cool off until room temperature.
Frost bars. Prepare frosting by whisking together in a bowl, strained Greek yogurt, maple syrup, cinnamon and vanilla extract. Then spread on top of baked oatmeal and using serrated knife cut into 16 bars.
Store: Refrigerate covered tightly with plastic for up to 7 days.