1 cup rolled oats
1/2 cup all-purpose flour
1/2 cup light brown sugar
1/4 cup sugar
1/2 teaspoon salt
4 ounces unsalted butter, cold and cubed
6 cups fresh berries, (e.g. strawberries, blueberries, raspberries)
Zest of 1 lemon
1/4 cup sugar
1/4 cup all-purpose flour