"I'm definitely a fan of One Girl Cookie's whoopie pies – specifically their pumpkin whoopie pie with cream cheese filling," the actress told PEOPLE.
And Russell isn't the only one going crazy for whoopie pies.
Apple-caramel flavored treats from Wannahavacookie, an online retail bakery, have been spotted in Rachael Ray's office.
Meanwhile, Maine and Pennsylvania have been battling for months over which state created the classic treat. John Smucker, the co-owner of Bird-in-Hand Bakery in Lancaster County, Penn., knows why his bakery's dessert is so in demand right now.
"They're the perfect cake sandwich, the right combination of soft, moist cake and sweet filling," he says.
Eager to try a whoopie pie? Make one yourself:
Pennsylvania Whoopie Pie
Makes 18 pies
Preheat oven to 350 degrees. In a large bowl, cream together ½ cup vegetable shortening, 1 cups sugar and 1 egg.
Add 1 cup butter milk, 2 cups sifted flour, ½ cup sifted unsweetened cocoa, and 1 tsp salt. Mix well.
Add ½ cup water and 1 tsp. baking soda and mix until smooth.
Using a small ice cream scoop, drop batter 2 inches apart onto greased baking sheets. Bake for 12 minutes. Cool cakes completely before filling.
Mix 3 ½ cups confectioner's sugar, 2 tbsp. flour, 1 tsp. vanilla, 1 ½ tsp. lemon juice, ¼ cup milk, ½ cup vegetable shortening on low speed until blended.
Then mix on high speed until fluffy. Scoop filling on half the cakes, then cover with another cake.
Adapted from Bird-in-Hand Bakery's recipe