In a bowl, whisk together the egg yolk, beer, mustard and vinegar. Drizzle in the oil, whisking constantly. Season with salt and pepper, then set aside.
With the rack in the middle position, preheat the oven to 400°F (200°C). Line a baking sheet with parchment paper.
Place the potatoes and sausages on the prepared baking sheet and add half of the oil (1 tbsp/15 ml). Toss to coat and season with salt and pepper. Bake for 25 minutes, stirring halfway through cooking.
In a bowl, toss the asparagus with the remaining oil and season with salt and pepper. Add to the baking sheet and continue cooking for 8 minutes or until the asparagus is al dente. Slice the sausages into 3/4-inch (2 cm) pieces.
Meanwhile, in a pot, bring the water and salt to a boil. Add the lentils and onion. Simmer over medium heat for 15 minutes or until the lentils are al dente. Drain, return to the pot and stir in 1/4 cup (60 ml) of the dressing.
Transfer the lentils to a serving platter. Top with the potatoes, asparagus and sausage slices. Drizzle with
the remaining dressing, as desired.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.