Roast for 8 to 10 minutes depending on your oven and the vegetables. Check with a sharp knife after 7 minutes. Pierce the thickest part of the broccolini stem or carrot.
If needed, roast some more. If you want a bit of char, move the sheet(s) close to the broiler element and broil till gently browned. I actually like spring vegetables without a char, but you do you!
If you are using a rose harissa paste instead of a powder, melt the butter and combine the two to drizzle over the vegetables
You can swap out the vegetables with autumn veggies if so desired. You may need to adjust steaming and roasting time.
Play with different seasonings. Instead of rose harissa, try freshly chopped thyme or dill, or even chopped mint. In the autumn switch to chopped fresh sage, rosemary and parsley.
Try using goat cheese, ricotta, mini bocconcini balls instead of feta if you so desire.