Preheat oven to 325°F. Line baking sheets with parchment paper.
In a medium bowl, combine oats, sugar, flour, salt, and baking powder.
1 cup old-fashioned rolled oats, 1 cup granulated sugar, 2 tablespoons all-purpose flour, ½ teaspoon fine sea salt, ¼ teaspoon baking powder
In a small bowl, beat the egg slightly with a whisk. Add the melted butter, vanilla, and almond extract and whisk thoroughly to combine.
1 large egg, ¼ cup unsalted butter, ½ teaspoon vanilla extract, ¼ teaspoon almond extract
Add the egg mixture to the dry ingredients and mix well. Stir in the almonds.
½ cup sliced or slivered almonds
Drop the cookie batter by teaspoonfuls about 4 inches apart. Use the back of the teaspoon to slightly flatten the mounds of batter. The more round the batter mounds are now, the more round the final cookies will be.
Bake for 13-15 minutes, until the sugar has stopped bubbling and the edges are golden brown.
Let the cookies cool on the baking sheets for 5-7 minutes; they should be nearly cool. Gently peel the cookies off the parchment and place on a wire rack to finish cooling.