Method

Preheat oven to 400°F.
In bowl, combine 1/4 cup each large-flake oats and brown sugar, 3 tbsp melted unsalted butter, 2 tbsp all-purpose flour and pinch fleur de sel. Spread mixture on parchment paper-lined baking sheet. Bake, stirring halfway through cooking time, until mixture is crispy and lightly browned, 10 to 12 minutes. Let cool, then break into pieces. (Make-ahead: Can be stored in airtight container at room temperature for up to 1 week.)  Makes 1/2 cup.