Preheat the oven to 350°F (175°C). Line two baking sheets with parchment paper and set aside.
In a large mixing bowl, cream together the softened butter, light brown sugar, and granulated sugar until light and fluffy, about 3 to 4 minutes using an electric mixer on medium speed.
Add the eggs one at a time, beating well after each addition. Then mix in the vanilla extract until combined.
In a separate bowl, whisk together the all-purpose flour, baking soda, ground cinnamon, and salt.
Gradually add the dry ingredients to the butter and sugar mixture, mixing on low speed until just combined.
Stir in the rolled oats until evenly distributed.
Add the sesame seeds, poppy seeds, dried minced onion, garlic powder, and 1 teaspoon flaky sea salt to the dough. Fold gently with a spatula until the seeds and spices are evenly incorporated.
Using a tablespoon or cookie scoop, drop rounded spoonfuls of dough onto the prepared baking sheets, spacing them about 2 inches apart.
Lightly sprinkle a pinch of flaky sea salt on top of each cookie dough mound.
Bake in the preheated oven for 10 to 12 minutes, or until the edges are golden brown but the centers remain soft.
Remove the cookies from the oven and allow them to cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely.