Here's a basic yellow cupcake batter that will stand up to being filled and decorated.

1 1/2 cups all-purpose flour
2 tsp. baking powder
1 tsp. salt
1 cup sugar
2 eggs
1 stick (1/2 cup) unsalted butter at room temperature
1 teaspoon extract (I prefer vanialla, but you can use almond extract or other flavor of your choice)
1/2 cup milk

Preheat oven to 350 degrees. Mix all the dry ingredients together and set them aside. Cream the butter and sugar until fluffy. One at a time add the eggs, mixing well after each is added. Add the extract. Alternate adding some of the flour and milk until you have all the flour and milk into the batter. Beat until batter is smooth.

Spoon the batter into cupcake liners, filling each one about 2/3 full. Bake for 20-25 minutes. Toothpick inserted into center will come out clean when they are done. Remove from oven and cool.