Dark Chocolate Bacon Cupcakes

Can you say big old flop?
It's rare I have trouble with a baking recipe but this one was horrible! The batter was very runny. Their middles sunk and I couldn't peel the paper off of the cupcake. Horrible! I threw them all out and quickly whipped up a batch of chocolate cupcakes with vanilla buttercream frosting.
Recipe from All Recipes.
Ingredients
12 slices bacon
2 cups all-purpose flour
1 cup unsweetened cocoa powder
2 cups white sugar
2 tsp baking soda
1 tsp baking powder
1/2 tsp sea salt
2 eggs
1 cup cold, strong, brewed coffee
1 cup buttermilk
1/2 cup vegetable oil
1 tbsp unsweetened cocoa powder, for dusting
Directions
Preheat oven to 375 ⁰F. Place bacon in a large, deep skillet. Cook over medium-high heat until evenly brown. Drain, crumble and set aside.
In a large bowl, stir together the flour, 3/4 cup cocoa powder, sugar, baking soda, baking powder and salt. Make a well in the center and pour in the eggs, coffee, buttermilk and oil. Stir just until blended. Mix in 3/4 of the bacon, reserving the rest for garnish. Spoon the batter into the prepared cups, dividing evenly.
Bake in the preheated oven until the tops spring back when lightly pressed, 20 to 25 minutes. Cool in the pan set over a wire rack. When cool, arrange the cupcakes on a serving platter. Frost with your favorite chocolate frosting and sprinkle reserved bacon crumbles on top. Dust with additional cocoa powder.