Microwave the potatoes, in a towel, until cooked through and soft. 2 medium potatoes will take about 10 minutes, turning over half way through cooking time. Time will depend on size of potatoes. Carefully cut potatoes in half lengthwise. Place potatoes skin side up on a cutting board and rub the outside skins with olive oil and sprinkle with kosher salt. Turn potatoes over and make deep parallel cuts through potato flesh, forming diamonds, and being careful not to cut all the way through skin.

Place potatoes and broccoli on a foil or parchment lined baking sheet. Toss broccoli with olive oil and garlic, salt and pepper. Drizzle potatoes with olive oil and season with salt and pepper. Roast in a 400 degree oven for 20 minutes or until broccoli is done and potato edges have crisped.

Put broccoli on top of potatoes and pour cheese sauce or grated cheese over all. Top with onions. Return to oven for 5 minutes to heat through, melt cheese and crisp onions.