Heat the oven to 400ºF. Bring a large pot of salted water to a boil.

• Peel and thinly slice the shallots.
• Finely chop the garlic.
• Trim the root ends of the asparagus, then cut on a diagonal into 1/8-inch-thick pieces.
• Thinly slice the mushrooms.
• Pick the leaves from the parsley and thyme sprigs, and coarsely chop the leaves.
• Cut the lemon in half, zest one half and juice the other.

On a sheet pan, roast the hazelnuts in the oven until lightly toasted and crisp, 8 to 10 minutes. Transfer to a plate to cool slightly. Using the side of a knife, lightly crush them. While the nuts roast, cook the vegetables.

In a pan over medium heat, warm 1 tablespoon oil until hot but not smoking. Add the shallots, season with salt and cook, stirring occasionally, until starting to soften, 2 to 3 minutes. Stir in the garlic and cook for about 30 seconds.
Add the asparagus and mushrooms and cook, tossing to coat, until just tender, 1 to 2 minutes.

Once the water is boiling, add the gnocchi to the pot, stir, and cook until they float to the top, 1 to 2 minutes. Using a slotted spoon, transfer the gnocchi to the pan with the vegetables. Add 1 cup pasta cooking water to the pan, then stir in the parsley and thyme and season with salt and pepper.
Reduce the heat to a simmer and cook until the liquid is slightly reduced and thickened, 1 to 2 minutes. Remove from the heat, then stir in the lemon zest and lemon juice, and season with salt to taste.

Transfer the gnocchi and sauce to individual bowls. Garnish with the ricotta and hazelnuts, and serve with the lemon half on the side.