Preheat the oven to 400º F.
Roll out pizza dough into a large rectangle. From the center of one of the short sides, cut a triangle with both legs meeting the second shorter side’s corners. This should leave you with one large, whole triangle and two smaller triangles. (They might be misshapen, but that’s okay!)
Line a sheet pan with parchment paper. Transfer the two smaller triangles to the parchment paper, molding the dough to meet in the middle to form one large triangle. Stretch and roll the dough as you need to match the general size and shape of your first dough triangle.
Spread spinach and artichoke dip over the triangle in the sheet pan. For less mess later on, thin out the dip ½” away from the outer edge. Top with grated or shredded cheddar.
Carefully lay the first dough triangle over the filling. Using a pizza slicer or large knife, make the “branches” of your tree by making horizontal cuts down either side of the tree, leaving 1” of the center intact.
Take each section of the tree starting at the top and twist. The first several branches will probably only need half a twist; as you get to the wider part of the tree, you’ll likely need to twist the dough two or three times.
Brush the beaten egg evenly across the top crust.
Bake for 24-26 minutes on the bottom rack. The bottom layer of dough will bake slower than the top, so make sure to check both layers before removing it from the oven.
Brush the top crust with melted butter and add any extra spices you’d like; I used garlic powder, thyme, and cayenne pepper.