Turn the oven on and heat it to 350 degrees.
To make the crisp: Put the flour, oats, walnuts, and salt in the bowl and mix well.
Slowly drizzle in the olive oil and maple syrup, mixing with a fork as you go. Mix until crumbly.
To make the filling: Put the berries and 1 tablespoon flour in the baking pan or pie plate and mix well. Top with the crisp mixture. Once the oven temperature has reached 350 degrees, put the pan in the oven and bake until the top is lightly browned and the berries are bubbling, 25-30 minutes. Serve hot, warm, at room temperature, or cold.