In a large pot over medium heat, warm the olive oil. Add the sausage and brown, breaking it up with a spoon, until golden, 8 to 10 minutes. Using a slotted spoon, transfer the sausage to a paper towel-lined plate. Leave the fat in the pot.
Add the onion, fennel and celery and cook until softened, 6 to 8 minutes. Add the garlic and cook, stirring, until fragrant, about 1 minute. Sprinkle in the flour and cook, stirring constantly, for 1 minute.
Add the wine and scrape up any browned bits from the bottom of the pot. Simmer until reduced by about half, about 2 minutes.
Add the stock, tomatoes, Parmesan rind and sausage and bring to a simmer. Add the lasagna noodles and cook, stirring occasionally to keep them from sticking together, until al dente, 10 to 15 minutes.
Remove the pot from the heat and discard the Parmesan rind. Stir in the cream and season with salt and pepper to taste.
Ladle into bowls and garnish with a dollop of ricotta, basil, fennel fronds and cracked black pepper.