Preheat your grill to medium-high. Fill a pan with water and bring to the boil. Halve both of the peppers and scoop out the seeds and membrane. Slice the peppers into thin strips. Trim the top and root off the fennel, keeping the soft fennel fronds for later, and thinly chop into 1cm-thick slices. Pop the peppers and fennel on a large baking tray lined with foil. Finely chop the rosemary leaves and scatter them over the veg. Drizzle over 1 tbsp oil and a pinch of salt and pepper, and toss to coat. Slide under the grill for 8-10 mins, turning halfway, till tender and slightly caramelised.
When the water in the pan is boiling, pour in the gnocchetti and sprinkle in a generous pinch of salt. Simmer for 8-10 mins, till tender with a little bite. When cooked, drain the pasta and rinse with cold water to cool. Shake the pasta dry and tip into a large bowl.
Meanwhile, make the salad dressing. Peel the garlic and crush or finely chop it. Slide into a small bowl. Squeeze in the juice from half the lemon. Whisk in 1 tbsp oil and a pinch of salt and pepper.
Scoop the roast veg into the bowl with the pasta and pour over the dressing. Tip in the rocket leaves and fold together till evenly distributed. Pile onto warm plates and serve, garnished with the soft fennel fronds.