Line a square 8x8 baking pan with parchment paper on all sides. Set aside.
Microwave the flour in a bowl for around 1-2 minutes, or until it's hot. You can also spread it out in a thin layer on a baking sheet and bake it in a 350 F/180 C oven for 5 minutes. If the flour is clumpy after heating, push it through a fine mesh strainer before using. In a mixing bowl, cream the butter, sugar, and brown sugar together for 2-3 minutes until light and fluffy.
Mix in the heavy cream, milk, and vanilla extract until combined.
Then mix in the flour, chocolate chips, and salt.
Press the cookie dough into a flat even layer in the prepared baking pan. Place the pan in the fridge to chill.
Heat the chocolate chips and cream in a bowl in the microwave or over a double boiler for 1-2 minutes, stirring occasionally, until smooth and lump free.
Fold in the vanilla extract and rice krispies until well combined.
Then use the spatula to spread the chocolate in an even layer over the cookie dough.
Sprinkle the top generously with flaky sea salt.
Chill the cookie dough bars in the fridge for at least 3 hours, or overnight.
When you're ready, pull them out to soften for 15-20 minutes. In between cuts, run the sharp knife under hot water and then wipe it clean. This will give you clean cuts and make it easier to cut through the hardened chocolate!