Blueberry Cupcakes with Lemon Buttercream Frosting and Blueberry Sauce

INGREDIENTS

1 1/2 cups

all-purpose flour

1 1/2 tsp

baking powder

1/2 tsp

salt

1/4 cup

butter (, melted)

2 tbsp

vegetable oil

1 cup

granulated sugar

large egg

1 tsp

vanilla extract

1 1/2 tsp

lemon zest ((the zest of about 1 large lemon or 1 1/2 small lemons))

1/4 cup

sour cream

2/3 cup

buttermilk

1 cup

frozen blueberries

1/2 cup

butter (, softened)

4 cups

powdered sugar

2 tbsp

heavy cream

2 tbsp

fresh lemon juice

1/2 tsp

lemon zest

Yellow food coloring (, optional)

2 tbsp

granulated sugar

1 tsp

cornstarch

1 1/2 cups

fresh or frozen blueberries

1/4 cup

water