Blackberry Jam Filled Lemon Cupcakes

I found a recipe for a lemon cake in Gourmet magazine and decided to modify it by adding a blackberry filling.Definately use cupcake liners for this recipe, otherwise the filling will spill out of the cupcakes and stick to the pan!

Ingredients:
For batter:
1 1/2 cups all-purpose flour
1 1/2 tsp baking powder
1/8 tsp salt
1/2 cup plus 1 tbsp. milk
Zest of one lemon
1/2 tsp. vanilla extract
1 stick unsalted butter, softened
3/4 cup granulated sugar
3 large eggs
For glaze:
1 cup powdered sugar
1/4 cup lemon juice
For filling:
about 1/2 cup seedless blackberry jam
1 tbsp lemon juice

Directions:
preheat oven to 350 degrees.
Whisk flour, baking powder, and salt together. In a small bowl, mix together milk, zest and vanilla. Beat butter and granulated sugar together until light and fluffy. beat in eggs one at a time. Mix the flour mixture into the butter mixture, alternating with the milk mixture. Line a muffin tin with cupcake liners, and fill each liner about 1/4 full of batter. make the filling by mixing the blackberry jam and lemon juice together. Add about a teaspoon of the filling to each cup, then top with remaining batter. bake the cupcakes for 35-40 minutes. For glaze, whisk the powdered sugar and lemon juice together until smooth. While still warm, dip each cupcake into the glaze and set on a plate to cool.