In a saucepan over medium heat, combine granulated sugar, 1/4 cup water, and unsalted butter. Stir gently until the sugar dissolves, creating a smooth mixture.

Allow the mixture to cook without stirring until it turns a deep amber color, about 5-7 minutes.

Carefully add 2 cups of water and 1/4 cup heavy cream, stirring continuously until the caramel is smooth. Remove from heat, then stir in the vanilla extract and a pinch of kosher salt. Set aside to cool.

Set your oven to 350°F (175°C) and line a baking pan with parchment paper.

In a bowl, whisk together 7 tbsp all-purpose flour, quick oats, 1 1/4 cups of all-purpose flour, baking powder, and 1/2 tsp kosher salt until well combined.

In another bowl, cream together 1/2 cup of unsalted butter and dark brown sugar until smooth and fluffy.

Beat in 1 large egg, 1 egg yolk, and 2 tsp vanilla extract until fully incorporated.

Gradually add the dry flour mixture to the butter mixture, mixing lightly until just combined.

Gently fold in semisweet chocolate chips, dark chocolate chips, and chopped walnuts or pecans.

Pour half of the cookie dough into your prepared baking pan and spread it evenly. Drizzle half of the cooled caramel over the dough.

Spread the remaining cookie dough over the caramel layer, then drizzle the rest of the caramel on top. Finish with a sprinkle of flaky sea salt.

Bake for about 30 minutes or until golden brown on top.

Allow the bars to cool completely in the pan before cutting them into squares.