Preheat your oven to 350°F (175°C). This ensures that the crisp will bake evenly.

In a mixing bowl, combine the fresh raspberries, granulated sugar, cornstarch, lemon juice, and vanilla extract. Gently toss the ingredients together until the raspberries are coated. This mixture will create a sweet and tangy filling.

Transfer the raspberry mixture into a greased 9-inch baking dish, spreading it evenly across the bottom.

In a separate mixing bowl, combine the old-fashioned oats, all-purpose flour, brown sugar, melted butter, sliced almonds, cinnamon, and salt. Stir until the mixture is well combined and crumbly. The melted butter helps bind the ingredients while creating a crunchy texture.

Sprinkle the oat mixture evenly over the raspberry filling in the baking dish. This will form a deliciously crunchy topping.

Place the baking dish in the preheated oven and bake for 25-30 minutes, or until the topping is golden brown and the raspberry filling is bubbling. Keep an eye on it to prevent burning.

Once baked, remove from the oven and allow to cool for at least 10 minutes before serving. This cooling time helps the filling set slightly.

Serve warm, optionally topped with a scoop of vanilla ice cream or whipped cream for an extra treat!