In a large pot (I use a dutch-oven), melt the butter with the olive oil over medium heat. Add the garlic and thyme and saute until the garlic is just starting to caramelize, about 4 minutes.
Warm the chicken broth in a separate pot on the stove until just steaming. Stir the rice and 1 tsp. salt into the garlic and thyme. Increase the heat to medium-high and toast the rice, stirring, about 4 minutes until the rice is just barely browning. Pour in the wine and add half of the lemon zest. Stir until the wine is absorbed into the rice.
Decrease the heat back to medium and stir in a few ladles of the hot chicken broth. Cook, stirring often, until the broth is absorbed, keeping a gentle simmer going. Continue this process, adding the chicken broth a ladle at a time and stirring until it is absorbed, until all the broth is gone.
Swirl in the lemon juice. Taste a small spoon of rice to check for doneness, it should be soft with just a slight chew to it.
While the rice is cooking, trim the tough ends off of the asparagus stalks and steam in the microwave until just softened (3-4 minutes). Chop into 1 inch pieces.
When the rice is cooked, stir in the asparagus pieces, remaining lemon zest, cream, and pecorino romano cheese, as well as freshly cracked black pepper, to taste.
If the risotto is too thick, it can be thinned with a little more broth. If it is too thin, it can be simmered a bit longer to thicken.
Serve topped with extra cheese and pepper, if desired.