Heat broth in small saucepan over medium heat to simmering; keep hot over low heat.
Heat 6 tablespoons (90 mL) of the butter in heavy 10-inch (25 cm) skillet or 2 1/2 quart (2.5 L) saucepan over medium heat.
When foam subsides, add onion; saute until onion is soft, about 5 minutes.
Stir in rice; cook and stir 2 minutes.
Stir in wine, salt and pepper.
Cook uncovered over medium-high heat, stirring occasionally, until wine is evaporated, 3 to 5 minutes.
Measure 1/2 cup (125 mL) of the hot broth; stir into rice.
Adjust heat during this step between medium and low to maintain simmer.
Cook uncovered, stirring frequently, until broth is absorbed.
Repeat this process of adding 1/2 cup (125 mL) broth and cooking until absorbed until a total of 2 cups (500 mL) broth has been added.
Meanwhile, crush saffron in mortar with pestle to a powder; stir in 1/2 cup (125 mL) of the remaining broth to dissolve saffron.
Add saffron-flavored broth to rice and cook until absorbed.
Continue adding remaining broth, 1/2 cup (125 mL) at a time, and cooking, until rice is tender but firm to the bite and mixture has slightly creamy consistency.
Not all the broth may be required.
Total cooking time will be about 20 minutes.
Remove risotto from heat.
Stir in remaining 1 tablespoon (15 mL) butter and the cheese.