Heat-treat the flour:Spread flour on a baking sheet and bake at 350°F for 5–7 minutes to kill any bacteria. Let cool completely.
Make the cookie dough layer:In a large bowl, beat softened butter with brown and granulated sugar until creamy. Add milk and vanilla, and mix until smooth. Stir in heat-treated flour and salt until a thick dough forms. Fold in mini chocolate chips.
Press into a pan:Line an 8×8-inch pan with parchment paper. Press cookie dough evenly into the pan and smooth the top. Chill in the fridge while you make the ganache.
Make the ganache:In a microwave-safe bowl, combine chocolate chips and heavy cream. Microwave in 30-second intervals, stirring between, until smooth. Stir in a pinch of salt.
Pour and chill:Pour the ganache over the chilled cookie dough layer and smooth it out. Chill in the fridge for at least 2 hours, or until fully set.
Slice and serve:Use the parchment to lift the bars out of the pan. Slice into 16 squares and devour. Store in the fridge for up to 1 week or freeze for longer.
