Preheat your oven to 375°F (190°C). This ensures that the cobbler will bake evenly.

In a large mixing bowl, combine the sliced strawberries and chopped rhubarb.

Add the granulated sugar, cornstarch, vanilla extract, and lemon juice. Stir gently until the fruit is well coated.

Let the mixture sit for about 10 minutes to allow the juices to release, which will enhance the flavor.

Transfer the fruit mixture into a greased 9x13-inch baking dish, spreading it evenly.

In a separate mixing bowl, whisk together the flour, baking powder, salt, and sugar.

Add the cold, cubed butter to the flour mixture. Use a pastry cutter or your fingers to work the butter into the flour until the mixture resembles coarse crumbs.

Pour in the milk and vanilla extract, stirring gently until just combined. Be careful not to overmix, as this can make the topping tough.

Drop spoonfuls of the biscuit topping over the fruit filling, leaving some gaps for the fruit to peek through.

Bake in the preheated oven for 35-40 minutes, or until the topping is golden brown and the filling is bubbling.

Remove from the oven and let cool for at least 10 minutes before serving. This allows the filling to set slightly.

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