1 1/2 cups all-purpose flour
1 cup white sugar
1/4 cup unsweetened cocoa powder
1 teaspoon baking soda
1/2 teaspoon salt
2 eggs, beaten
3/4 cup water
1/2 cup vegetable oil
1 tablespoon apple cider vinegar
1 teaspoon Mexican vanilla extract
1 (8 ounce) package cream cheese, softened
1/3 cup white sugar
1/8 teaspoon salt
1 cup semisweet chocolate chips
1 cup chopped walnuts
Preheat oven to 350 degrees F (175 degrees C). Line 18 muffin cups with paper cupcake liners.
Mix flour, 1 cup sugar, cocoa powder, baking soda, and 1/2 teaspoon salt in a large mixing bowl. Add eggs, water, vegetable oil, vinegar, and vanilla extract; mix well. Pour batter into prepared muffin cups.
Beat cream cheese, 1/3 cup sugar, and 1/8 teaspoon salt together in a separate bowl with an electric hand mixer until the sugar is fully incorporated into the cream cheese. Fold chocolate chips into the cheese mixture. Drop by tablespoonfuls into center of each cupcake; sprinkle with walnuts.
Bake in preheated oven until a toothpick inserted into the middle of a cupcake comes out clean, 25 to 30 minutes. Cool in the pans for 10 minutes before removing to cool completely on a wire rack.