Chocolate Chip Sour Cream Coffee Cake

Sheet cakes are our current love - the perfect low key, fuss-free and easily transportable dessert that can feed a crowd. This one is delightfully moist with just the right amount of sweetness. 

Chocolate Chip Sour Cream Coffee Cake
~ from Smitten Kitchen
1/2 cup (114g) unsalted butter, room temperature
1 1/2 cups (324g) sugar
3 eggs, separated
1 1/2 tsp (11g) vanilla
2 cups sour cream
3 cups (417g) Flourist Sifted Red Fife Flour
1 tsp baking powder
1 1/2 tsp baking soda
3/4 tsp salt

Topping
2 cups (350g) bittersweet or semisweet chocolate chips
1/3 cup 72g) sugar
1 tsp cinnamon

Preheat oven to 350°F. Line a rectangle 9x13-inch pan with parchment paper. In a large bowl, whip egg whites until stiff. Place in a separate bowl and set aside. 

Using the same bowl (no need to clean it), cream together the butter and 11/2 cup sugar until fluffy. Beat in egg yolks and vanilla. 

Whisk together Flourist Sifted Red Fife Flour, baking powder, baking soda and salt in a separate bowl.

Mix in the sour cream in 3 batches and the dry ingredients in 2 batches to the butter mixture, alternating sour cream-dry-sour cream-dry-sour cream. The batter should be thick and smooth. Gently fold the whipped egg whites into the batter with a spatula. 

For the topping, combine the sugar and cinnamon together. Spread half of the batter in the bottom of a prepared cake pan and spread smooth with a spatula. Evenly sprinkle half of the cinnamon-sugar mixture and 1 cup chocolate chips over top. Add the remaining batter, spread smooth and repeat with the rest of the topping. 

Bake for 40 to 50 minutes, until a toothpick inserted into the center comes out clean. Let cool in pan before slicing and serving.