1-First Step: Brown the Butter Start by browning 1 cup unsalted butter in a medium skillet over medium heat. Stir frequently as the butter bubbles, foams, and develops golden browned bits releasing a nutty aroma, about 5-7 minutes. Immediately transfer browned butter to a heatproof bowl to cool for 5-10 minutes, ensuring it stays warm but not hot to avoid excessive dough spreading.

2-Second Step: Combine Dry Ingredients In a separate large bowl, whisk together 2 to 2 1/3 cups all-purpose flour, 1 teaspoon baking soda, ½ teaspoon baking powder if using, and ½ teaspoon salt. Add 2 cups old-fashioned oats and stir until evenly mixed.

3-Third Step: Mix Wet Ingredients In another bowl, stir browned butter with 1 ¼ cups brown sugar and ½ cup granulated sugar (optional) until smooth and uniform. Add 2 room temperature eggs one at a time, mixing well after each addition. Stir in 1 tablespoon vanilla extract.

4-Fourth Step: Combine Wet and Dry Ingredients Gradually add the dry oat-flour mixture to the wet brown butter mixture gently, stirring until just combined. Avoid overmixing. Fold in 6 oz semisweet chocolate chips or a mix of chunks and chips for varied texture and chocolate richness.

5-Fifth Step: Shape and Bake Line baking sheets with parchment paper. Using a tablespoon or 2-tablespoon scoop, drop rounded dough balls onto sheets, spacing them about 2 inches apart. Slightly flatten each ball with your hand or the back of a spatula. Bake in a preheated 350°F (175°C) oven for 8 minutes. Remove cookie sheets, rotate and gently tap cookies to flatten further without breaking. Return to oven and bake for an additional 2-3 minutes until edges set but centers remain soft.

6-Final Step: Cool and Serve Remove cookies from oven and sprinkle warm cookies with flaky sea salt if desired. Let cool on baking sheets for 5-10 minutes to firm up. Serve warm or store in airtight containers at room temperature for up to 3-4 days.