Coffee Cookie Bars (Cookie Toffee Bars)

Ingredients

• 1 cup softened unsalted butter (2 sticks, 16 Tbsp.)
• 1 cup dark brown sugar (packed)
• 2 cups all-purpose flour (spooned and leveled)
• 1 cup milk chocolate chips
• 2 Tbsp. instant coffee granules
• 1/2 tsp. baking powder
• 1/2 tsp. salt
• 1/2 tsp. vanilla extract
• 1/2 Tbsp. espresso powder (optional)
• 1 (14 oz.) can sweetened condensed milk
• 2 Tbsp. unsalted butter
• 2 tsp. vanilla extract
• 2 tsp. flaky sea salt