1/2cupunsalted butter, at room temperature(113 grams)
1/3cupdark brown sugar(70 grams)
1/2cupheavy cream(125 ml)
Vanilla Buttercream Frosting:
4cupspowdered sugar, sifted (1 lb, 455 grams)
1cupunsalted butter, at room temperature (226 grams)
1/4cupheavy whipping cream
Food coloring, optional
Sprinkles for decorating, optional
To make the graham crackers:
In a bowl combine the whole wheat flour, all-purpose flours, baking powder, baking soda, salt, cinnamon and nutmeg. Set aside.
In the bowl of a stand mixer fitted with a paddle attachment, or in a large bowl with a hand-held mixer, beat the butter, brown sugar, honey and vanilla until pale and creamy, scraping down the bowl as needed. Add the flour mixture in 4 additions, alternating with the heavy cream. Scrape down the bowl between each addition.
Divide the dough in two and shape into 2 rectangular disks. Cover with plastic wrap and chill for at least 2 hours and up to several days.
When ready to bake, preheat oven to 350F/175C. Line a sheet pan with parchment paper.
On a lightly floured surface, roll one disk of dough out at a time into a rectangle about 1/8-inch thick. Use a sharp knife or pastry wheel to cut the dough into roughly 3-inch squares. You may want to use a ruler (I did).
Place the squares onto the prepared sheet pan 1/4 inch apart. Sprinkle with coarse sugar, if using. Bake until edges just begin to turn brown, about 12 minutes. Let cool 5 minutes on the pan, then transfer to a wire rack to cool completely.
Graham crackers can be stored in an airtight container at room temperature for up to 1-2 weeks.
To make the frosting:
In the bowl of a stand mixer fitted with a paddle attachment, or in a large bowl with a hand-held mixer, mix all of the ingredients on low speed until it starts to come together.
Increase speed to high and beat for 3-4 minutes until frosting is fluffy, pausing once or twice to scrape the bowl down. If adding food coloring, mix in now until smooth.
Use frosting as desired to cover cakes, cupcakes, cookies, etc.
Store frosting at room temperature for 1-2 days, in the fridge for up to 2 weeks or in the freezer for up to several months.
To assemble cookie sandwiches:
Spread vanilla frosting on a graham cracker and top with another cracker. Decorate with sprinkles as desired. Store sandwiches in an air-tight container for several days. (I like to store mine in the fridge so the frosting is somewhat solid and doesn't squish out while you eat it.)
For a quick shortcut, use store-bought graham crackers.