1 cup flour
3/4 teaspoon baking powder
1/2 teaspoon baking soda
1/4 teaspoon table salt
14 tablespoons butter, slightly softened
1 cup sugar
1/4 cup brown sugar, packed
1 teaspoon vanilla
2+1/2 cups old-fashioned rolled oats
coarse sea salt
Preheat oven to 350 degrees. Whisk dry ingredients (through salt) together. Cream butter and sugars until light and fluffy. Mix in egg & vanilla, then stir in dry ingredients and oats. Divide dough into 24 equal portions (about 2 tablespoons each) and roll into balls. Place on three parchment-lined baking sheets, and flatten dough slightly to about 3/4" thickness. [These do spread quite a bit, so don't put more on a sheet unless you're making smaller cookies.] Lightly sprinkle sea salt over all the cookies. Bake one sheet at a time for 13-16 minutes, rotating pan halfway through, until edges look crisp. Transfer baking sheets to wire racks and cool on sheets.
**Update** The Orange-Almond variation is quite good too, although I think I still prefer the plain salted recipe. To make the Orange-Almond, add 2 teaspoons of orange zest to the butter & sugars when you cream them. Then, decrease the oatmeal to 2 cups and add 1 cup chopped, toasted almonds. Do not sprinkle with sea salt.