1.Cook sausages in a heated 6-litre (24-cup) pressure cooker until browned. Remove from cooker; slice thinly.
2.Heat oil and butter in cooker; cook onion, fennel and garlic, stirring, until vegetables soften. Add rice; stir to coat in butter mixture. Add wine; simmer, uncovered, until liquid is absorbed. Add stock and the water; secure lid. Bring cooker to high pressure. Reduce heat to stabilise pressure; cook 7 minutes.
3.Release pressure using the quick release method; remove lid. Add sausage and peas; cover, stand 5 minutes. Stir in half the parmesan and thyme; season to taste. Serve risotto sprinkled with parmesan.