Aunt Susan and I went blueberry-picking together with our young children in Amagansett. We decided to have a contest to see which team could pick the most berries. The smushed ones did not count. We had so much fun that we all forgot who won! I still remember how much we laughed. This crisp always reminds me of that magical day.
Preheat the oven to 375 degrees.
Toss the blueberries, sugar, lemon zest, and juice together in a bowl. Pour into a 9-inch square baking dish. In the bowl of a food processor, combine the flour, brown sugar, oats, and butter and pulse until the mixture resembles crumbs. Spread this over the berries. Bake until golden on top, 40-45 minutes.