Chocolate Chip Sour Cream Coffee Cake

Cheers cheers ol' chap, may we raise our glasses to the sun and the moon, the earth and the water, and to the great abyss. I feel like saying that in a uppity British accent when I eat this. It is my favourite coffee cake. We ate it in one day. Nobody can resist this perfect cake. Whenever I am in doubt as for what to bring to coffee, dinner or to just straight eat in general.

I don't know how else to tell you to eat this but please please do. 

Chocolate Chip Sour Cream Coffee Cake
From smitten kitchen

cake
1/2 cup unsalted butter (1 stick, 4 ounces or 113 grams) at room temperature
1 1/2 cups (300 grams) granulated sugar
3 large eggs, separated
1 1/2 teaspoons vanilla extract
2 cups (16 ounces) sour cream
3 cups (375 grams) all-purpose flour
1 teaspoon baking powder
1 1/2 teaspoons baking soda
3/4 teaspoon kosher salt

filling and topping
2 cups milk chocolate chips
1/2 cup (100 grams) granulated sugar
1 teaspoon cinnamon

Preheat oven to 350°F. Butter a 9-x-13-inch baking pan. If not nonstick coated, cover the bottom with a rectangle of parchment paper. Set pan aside. In a large bowl, cream butter and 1 1/2 cups sugar. Beat in egg yolks and vanilla. Sift flour, baking soda, baking powder and salt together into a separate bowl. Alternately mix in sour cream and then dry ingredients into butter mixture until both are used up and the batter is smooth and very thick. In a medium bowl, beat eggs whites until stiff, then fold into batter. In a small dish, whisk together sugar and cinnamon for filling and topping. Spread half the cake batter in the bottom of prepared pan. Sprinkle with half of cinnamon-sugar mixture and 1 cup of chocolate chips. Dollop remaining cake batter over filling in spoonfuls. Use a rubber or offset spatula to gently spread it over the filling and smooth the top. Sprinkle batter with remaining cinnamon-sugar and remaining chocolate chips. With the palm of your hand, ever-so-gently press the chocolate chips a bit into the batter. No need to submerge them, you just want to make sure they adhere bit. Bake for 40 to 50 minutes, rotating halfway through, until a tester inserted into the center of the cake comes out clean. Serves 24.