Place butter in saucepan on medium-high heat to melt. Swirl or stir the butter with a wooden spoon as it starts to foam. Continue to melt until butter begins to bubble and turn brown. Scrape melted butter into a oblong small pan or rectangular Tupperware and refrigerate for at least 4 hours or overnight. When the brown butter is solid again, slice into ½-inch cubes and set aside.
In a large mixing bowl combine your washed berries with the cornstarch, chopped basil leaves and 1 TBSP maple sugar. Set aside.
In a mixing bowl, sift together flour, baking powder, nutmeg, salt, zest and maple sugar. Cut in the cold brown butter (using your fingers or a pastry cutter) until mixture resembles a coarse meal. Work the butter into the dry ingredients until some of the butter flakes are the size of gravel. Stir together the buttermilk and vanilla and then add to the flour mixture, stirring enough to make a soft dough.
Lightly grease either 4 miniature cast-iron skillets or one large cast iron pan or baking dish. Pour berry mixture among skillets or into your preferred baking pan. Place large drops/spoonfuls of the biscuit mixture over the berries.Bake at 400° for 20 to 24 minutes or until fruit bubbles and crust is golden brown.
Recipe by Kitchen Belleicious at https://kitchenbelleicious.com/2014/04/29/brown-butter-maple-berry-skillet-cobbler/