Start by breaking down the fennel by removing the two outermost layers of the bulb. Trim the end, and cut the stalks off from where they protrude from the bulb. Remove some of the feathery fronds from the stalks and set aside for later. Roughly chop all the scraps and place them in a 2-quart pot. Pour the cold water over the fennel scraps, plunk in the whole clove of garlic (unpeeled is fine), and place over medium heat. Bring it to a gentle simmer, stir in a heaping ¼ t-spoon of kosher salt, and reduce the heat to low, simmering for 25 minutes uncovered. Once the broth is done, strain it into a large liquid measuring cup through a fine mesh sieve—you should have 5 cups left. Return to the saucepan, cover, and place over very low heat to just keep warm (with the parm rind, if using).
Preheat the oven to 475°
Cut the fennel into ¼” thick wedges, keeping the core in contact to keep the wedges together. Toss the fennel in 1 tablespoon of the olive oil and place in a small roasting tray.
Set aside for now—this needs 15 – 20 minutes to roast, so you’ll put it in the oven once you start stirring liquid into the rice.
Next, add the remaining 1 tablespoon of olive oil and sausage links to a Dutch oven and place over medium heat. Allow them to gradually warm and come up to temperature, cooking on one side for a few minutes until lightly crisped and bronzed, before turning them over. Cook an additional 2-3 minutes.
Pour in the wine and cover with the lid, turning the flame down to low and steam the sausages for about 5 minutes.
Remove the sausages to a foil lined plate and cover tightly with foil and set aside.
Pour the wine out into a heatproof liquid measuring cup.
Heat 3 tablespoons of butter and a few drops of olive oil in the Dutch oven over medium heat. Once the butter is melted and sizzling, add the shallots, and sauté for a few minutes until they are soft. Add in the minced garlic, thyme and some salt. Stir around for just a minute.
Add the rice and stir about, toasting in the fat for a few minutes until the grains become slightly opaque and smell a little nutty without taking on any color.
Pour in the reserved wine and stir around into the rice vigorously, turning down the heat to medium low immediately. Let it bubble a little until the wine is mostly absorbed in the rice.
Put the fennel in the oven at this time.
Now, a ladleful at a time, pour the stock into the rice, constantly stirring. This helps the rice to release its starches all the while absorbing the stock. Do not add any more stock until the rice has almost absorbed all of its current stock. In all, the stock absorbing should take about 20 minutes.
In the last few minutes, slice the sausage on a bias into ½” thick pieces, remove the fennel from the oven—which should be bronzed and soft—and add to the risotto, along with any juices that collected on the sausage plate.
Turn off the heat, stir in the Parmesan and remaining tablespoon of butter and serve immediately, with parsley or the reserved fennel fronds sprinkled over top of it. Serve this immediately for optimal quality.