Heat oil and half the butter in a large, deep frypan on medium-low heat. Cook onion and garlic for 3-5 minutes until soft. Turn heat to medium-high, add rice and stir to coat. Add wine and stir for 1 minute. Add stock a ladleful at a time, stirring and allowing each to absorb before adding the next, until rice is cooked but still al dente. Add asparagus with final ladleful of stock (risotto should take 15-20 minutes). Stir in cheese, remaining butter and 1/2 cup (125ml) boiling water. Remove from heat, stir in rind and parsley. Season and serve with extra shaved parmesan.