Strawberry crumble - Borges India

Ingredients

• 1 cup softened butter cut into small cubes
• 1 cup brown sugar
• 1 cup flour
• 1 cup rolled oats
• 3 cups diced strawberries
• ¼ cup cornstarch
• 2 tablespoons white sugar
• 2 tablespoons red wine vinegar
• 1 lemon