This is quite rich but it is super easy to make and the cake is wonderfully moist.Plan Ahead Note: the butter needs to be softened to room temperature.
Preheat oven to 350°. Coat a 9" round cake pan with cooking spray. Line the bottom with parchment paper and coat the paper with cooking spray.
Whisk all-purpose flour, whole-wheat flour, granulated sugar, cocoa, baking soda, and ½ teaspoon salt in a large bowl.
Whisk water, oil, vinegar, almond extract, and ½ teaspoon vanilla in a small bowl.
Add the wet ingredients to the dry ingredients and stir until smooth.
Pour the batter into the prepared pan. Tap it lightly on the counter to remove any air bubbles.
Bake until a toothpick inserted in the center comes out with just a couple of crumbs attached, 25-30 minutes. Let cool in the pan on a wire rack for 10 minutes, then turn out onto the rack.
Remove the parchment and let cool completely, about 45 minutes.
Filling
Prepare the filling by beating the butter in the bowl of a stand mixer fitted with the whisk attachment on medium speed for 1 minute.
Add confectioner's sugar, ½ cup at a time, until completely incorporated.
Add mint extract and vanilla, then ¼ teaspoon of salt and food coloring.
Add 2 Tablespoons of half-and-half and beat, scraping down the sides as necessary, until fluffy and light.
Using a serrated knife, cut the cooled cake in half horizontally. Place the bottom layer, cut-side up, on a serving plate.
Spread with the filling and top with the other layer, cut side down.
Glaze
Heat the half-and-half over low heat on the stove until hot and add the chocolate chips, stirring until melted.
Add salt and whisk until glossy. Let cool for 5 minutes.
Spread glaze over the cake. Refrigerate for up to 2 days and serve at room temperature.