Heat the oil in a large skillet over medium heat.
Add the broccoli Romanesco and sliced garlic cook until brightly colored and starting to turn golden brown. This should take about 9 minutes. Remove and reserve a few pieces for garnishing but leave the rest.
Add water and 1 teaspoon of salt to the skillet. Cover and cook until the broccoli Romanesco until tender, about 10 minutes. Drain any remaining liquid from the skillet.
In your food processor or blender, puree half the broccoli Romanesco and transfer to a large bowl. Puree the remaining broccoli Romanesco.
In a separate saucepan, bring the milk and cream to a gentle simmer.
Add the milk and cream mixture to the food processor with the second batch and pulse to combine. Add this mixture to the first batch in the bowl and mix gently together.
Add the Parmigiano-Reggiano, season with salt and pepper and mix together. Taste and adjust seasonings.
Garnish with the reserved broccoli Romanesco and a little more of the Parmigiano cheese.
Serve as a side dish.