Step 1: Make the Cookie Dough
Let’s dive in—grab a bowl and cream 1/2 cup unsalted butter, 1/2 cup granulated sugar, and 2/3 cup packed light brown sugar with a mixer on medium ‘til fluffy (I love that doughy start!). Add 1/4 cup milk and 2 tsp vanilla—mix ‘til smooth (my kitchen’s humming with vanilla vibes!). Stir in 2 cups flour and 1/2 tsp salt, then fold in 1 cup mini chocolate chips—scoop 15 balls with a 1 1/2-tbsp scoop, flatten slightly, and chill on wax paper with the leftover dough (I sneak a taste—it’s irresistible!).

Step 2: Preheat and Prep
Crank your oven to 350°F—spray three 8-inch pans with non-stick spray and line the bottoms with parchment rounds (I love that slick prep!). Take a sec to breathe—this is gonna be a cookie dough wonder, and you’re already rocking it!

Step 3: Mix the Dry Cake Base
In a small bowl, whisk 3 cups flour, 2 tsp baking powder, and 1 tsp salt—set aside (I love that floury puff!). In a glass, mix 1 cup whole milk with 2 tsp vanilla—set aside too (my heart’s racing with anticipation!). This is the fluffy foundation!

Step 4: Cream the Cake Wet Mix
In a big bowl, cream 1 1/2 cups unsalted butter and 2 cups sugar with a mixer on medium-high for 3-5 minutes—don’t rush, let it get light and fluffy (I grin every time it fluffs up!). Add 3 large eggs one at a time—mix ‘til smooth, then add 1/2 cup Greek yogurt (I love that tangy zing!).

Step 5: Combine Cake Batter
Alternate adding the flour mix and milk mix—start and end with flour, three dry and two wet additions (I feel pro layering it in!). Fold in 1 cup mini chocolate chips—divide evenly between pans, about a third each (I smooth it with glee!). Push 5 chilled cookie dough patties into each pan—cover with batter (I’m drooling already!).

Step 6: Bake the Layers
Bake for 30-35 minutes—check with a toothpick ‘til clean, rotate halfway if needed (I watch them rise with joy!). Cool in pans 20 minutes—run a knife around, turn onto racks, peel off parchment, and chill in the fridge for an hour (I count the minutes!).

Step 7: Whip the Buttercream
Cream 1 1/2 cups unsalted butter and 3/4 cup packed light brown sugar—add 5 cups powdered sugar and 1 cup flour in batches, pouring 1/4 cup milk between each (I love that creamy swirl!). Mix in 2 tsp vanilla and 1/2 tsp salt—hold the 1/2 cup chips for later (I sneak a taste—it’s dough heaven!).

Step 8: Assemble the Cake
Place one chilled layer on a plate—spread a heaping scoop of buttercream, stack the next, repeat, then top with the third (I feel like a stacking pro!). Chill the naked cake 20 minutes—mix the chips into the leftover buttercream, then frost the outside (I swirl it with glee!).

Step 9: Make the Ganache
Chop 4 oz bittersweet chocolate—heat 4 oz heavy cream in the microwave ‘til bubbling, pour over chocolate, and whisk ‘til smooth (I love that glossy melt!). Add 2-3 tsp vegetable oil ‘til it drips right—test with a whisk (I feel fancy perfecting it!).

Step 10: Drip and Decorate
Pour ganache over the chilled cake—push to the edges with an offset spatula for drips (I go slow and grin!). Crumble leftover cookie dough over the top—slice and serve (that first bite’s pure cookie joy, and you made it happen!). Store in the fridge—bring to room temp for best taste!