Bring 1 liter of water, 1 teaspoon of butter, lemon juice and salt to the boil.
Add the asparagus and cook for about 10 minutes, then drain and collect the brew, about 750 ml of it.
Heat 1 tablespoon butter in a pan. Peel and chop the onion and sauté in the butter. Add the rice and sauté for about 2-3 minutes until translucent. Deglaze with the wine and allow to evaporate, then add a little asparagus stock.
Now cook for about 15-20 minutes, gradually pouring in the remaining asparagus stock.
After about 12 minutes of cooking, add the asparagus pieces.
Stir in the remaining butter with the grated pecorino cheese.
Rinse the fish, pat dry, season with salt and pepper.
Heat the butter and fry the fish in it for 2 minutes. Halve the cherry tomatoes, add and season with salt and pepper.
Mix the herbs with the oil and pecorino in a blender. Season to taste with salt and pepper.
Serve the fish with the tomatoes and risotto, spread the pesto on top.