01 - Bring a large pot of salted water to a boil. Add spaghetti and cook according to package instructions until al dente. Reserve 1/3 cup pasta water, then drain.
02 - Heat a nonstick skillet over medium. Cook diced pancetta until crisp, stirring occasionally. Remove from heat and set aside.
03 - In a mixing bowl, whisk together eggs, grated Parmesan, heavy cream (if using), a pinch of salt, and generous black pepper.
04 - Return drained spaghetti to the pot, removed from heat. Add egg-cheese mixture, stirring quickly and vigorously to evenly coat the pasta. Blend in reserved pasta water a little at a time for desired creaminess.
05 - Mix in cooked pancetta and unsalted butter until the butter melts and pasta appears glossy.
06 - Place a clean cylindrical food mold or tin can on a serving plate. Twirl one-fourth of the pasta into the mold and press gently to shape a tower. Carefully remove the mold.
07 - In a small bowl, combine whipped cream cheese and chopped chives. Spread a dollop on each pasta tower as the 'icing.'
08 - Sprinkle towers with diced bell peppers, extra chives, and rainbow sprinkles if desired. Decorate with edible flowers or microgreens.
09 - Serve immediately for optimal texture and visual appeal.