Preheat oven to 350-degrees.
Place the butter in a small baking dish* that has been sprayed with a cooking spray. Melt in a 350-degree oven, about 10 minutes.
While the butter melts, stir together the flour along with 1 cup of the sugar, baking powder, nutmeg and chopped pecans.
Whisk together the half and half with the vanilla extract, ¼ teaspoon of the lemon extract and 1 teaspoon of the lemon juice. Pour into the flour and sugar mixture, stirring to blend together.
Using a scoop or spoon, drop dollops of the batter over the top of the melted butter. Set aside while you prepare the berries.
Toss the blackberries in a saucepan with ¾ cup of the remaining sugar, the remaining lemon extract, lemon juice and the lemon zest. If the blackberries are really tart you can add all the remaining sugar. Gently stir to warm the berries over medium-low heat just until the sugar is almost dissolved, about 3 to 5 minutes.
Spoon the blackberries over the top of the batter. Bake the cobbler in a 350-degree oven for about 50 minutes, or until the top is puffed and golden. Let the cobbler rest about 10 to 15 minutes before serving.