Step 1

Make the filling: In a medium pot, melt butter over medium heat. Add apples, tossing to coat in the butter. Add lemon juice, vanilla, brown sugar, cinnamon, ginger, nutmeg and salt and stir to combine. Continue to cook, stirring occasionally, until the sugar dissolves and the apples start to soften, 5 to 6 minutes.

Step 2

In a small bowl, whisk together granulated sugar and flour. Add to the pot and stir well to combine. Stir constantly until the mixture thickens, 2 to 3 minutes. (If you'd like to make it ahead of time, the filling will keep refrigerated for up to 3 days.)

Step 3

Heat oven to 375 degrees. Lightly grease a 9-by-13-inch pan with a thin layer of butter or a coating of nonstick spray, and scoop the filling into the pan.

Step 4

Prepare the cobbler: In a medium bowl, whisk the flour, brown sugar, cinnamon, baking powder and salt together to combine. Add the butter and toss well until each piece is coated fully with flour. Use your hands or a pastry cutter to cut the butter into the flour until the mixture resembles a coarse meal; the butter should be almost completely worked into the flour.

Step 5

Make a well in the center of the bowl, then add the buttermilk, egg and vanilla. Use a fork or small whisk to first beat the egg lightly, then stir all the ingredients together until well combined.

Step 6

Using a spoon, drop the batter in large dollops all over the cobbler. (Most of the surface will be covered, but some of the filling should still be visible.) Generously sprinkle turbinado sugar over the surface.

Step 7

Transfer to the oven and bake until the filling is bubbly and the biscuit topping is golden brown, 40 to 45 minutes. Cool at least 10 minutes before serving warm.