These are probably my most popular cookie recipe of all time!

Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper.
In a large mixing bowl, combine the oats and sugar.
Stir in the melted butter, egg, and vanilla extract until well blended.
In a separate bowl, whisk together the flour, baking powder, and salt.
Gradually add the dry ingredients to the wet mixture, stirring until just combined.
Drop teaspoonfuls of dough onto the prepared baking sheets, spacing them about 2 inches apart to allow for spreading.
Bake for 8-10 minutes or until the edges are golden brown.
Let the cookies cool on the baking sheets for a few minutes before transferring them to wire racks to cool completely.
Variations & Tips
For a twist, you can add a handful of chocolate chips or dried fruit like raisins or cranberries to the dough before baking. If you prefer gluten-free cookies, substitute the all-purpose flour with a gluten-free flour blend. For an extra flavorful batch, sprinkle a pinch of cinnamon or nutmeg into the mix. And if you're looking to up the protein, try adding a spoonful of peanut butter or almond butter to the dough.