How to Make It
In a medium saucepan, cook the olive oil, garlic and butter over moderate heat, whisking frequently, until the garlic just starts to color, about 7 minutes. Whisk in the anchovies and cook, whisking, until the garlic is golden, 5 to 7 minutes more. Transfer the bagna cauda to a heatproof medium bowl and let cool slightly. Whisk in the crushed red pepper and let the bagna cauda cool completely, stirring occasionally. Season with salt.
Meanwhile, in a food processor, pulse the sausages until finely ground. In a large skillet, combine the ground sausage with 1/2 cup of water and cook over high heat, stirring frequently, until the water evaporates and the sausage is rendered, about 5 minutes. Add the canola oil and cook over moderately high heat, stirring constantly, until the sausage bits are browned and crisp, about 7 minutes more. Using a slotted spoon, transfer the crispy sausage to paper towels to drain.
In a small bowl, mix the chives with the parsley, dill and mint. In a medium bowl, whisk the Kewpie mayo with the crème fraîche, lemon juice and 1/4 cup of the mixed herbs. Season the herbed dressing with salt.
Spread the herbed dressing in 8 very shallow bowls or on a platter. Arrange the tomatoes on top. Spoon some of the bagna cauda on top, then sprinkle with the crispy sausage, remaining mixed herbs and fleur de sel. Serve right away.
Look for Chinese sausage and Kewpie mayonnaise at Asian markets.