Preheat oven to 350 degrees and spray a donut pan with non-stick cooking spray. In a large bowl, whisk eggs then slowly add melted butter and whisk until slightly thickened. Add in milk and yogurt and whisk to incorporate. Add dry pancake mix and whisk until smooth.
Place two tablespoons of batter into each donut well and spread evenly. Bake 12-14 minutes, until the edges begin to turn golden. Remove from oven, allow donuts to cool 5 minutes in the pan, then carefully remove and cool completely on a wire rack. Repeat with remaining batter.
To make the chocolate glaze, in a large bowl, whisk together the powdered sugar and cocoa powder. Slowly add the milk and vanilla and continue whisking to make a smooth glaze. Set aside. Place the top of each donut into the glaze, twisting slightly to evenly coat. Place back on the cooling rack.
To make the frosting, use an electric hand blender to whisk the butter and yogurt until smooth. Slowly add the dry frosting mix and blend until fully incorporated. Place frosting into a piping bag or plastic ziplock bag. Cut off the tip of the bag and pipe a spider web design onto each donut. Enjoy immediately!