You can use zucchini, yellow summer squash, pattypan, or just about any other tender summer squash you can get your hands on in this recipe.
1 lb. new potatoes
3 tbs. butter, plus more for greasing
2/3 c. parmesan cheese, freshly grated
1/2 c. grated fontina or taleggio cheese
1 lb. zucchini or summer squash
1 bunch scallions, sliced, including some of the greens
1/4 c. mixed summer herbs (I used chives, parsley, and a little oregano)
1/3 c. milk
salt and pepper
Cook the potatoes in salted, boiling water until just barely tender, about 15 minutes. Drain, put in a bowl, and mash with a potato masher or the back of a fork. Stir in 1 tablespoon of the butter, the parmesan and fontina, and let cool slightly. Slice the largest of your squash on the diagonal into very thin rounds.
Preheat the oven to 350. Grease an ovenproof gratin dish with a little butter. Dice the remaining squash. Melt 2 tbs. butter in a large pan and saute the squash along with the scallions over medium heat for 5 minutes. Season with salt and pepper, lower the heat, pour in the milk, and cook, stirring, until it has been totally absorbed. Remove the pan from heat and stir the squash mixture into the potatoes. Add the herbs, and season with salt and pepper.
Line the gratin dish with the sliced squash, then top it with the potato mixture, smoothing the top with a spatula. Sprinkle some paprika over the top, and bake for 30 minutes.