For the charred poblanos and sides: Preheat the oven to 375 degrees F. Put the poblanos directly on top of the burner on high heat, turning with tongs until completely charred black, about 5 minutes. Place in a bowl and cover with a dish towel for 10 minutes. Rub off the skin with your hands or a paper towel, remove the seeds and cut into strips. Reserve.
Heat the vegetable oil in a large skillet over medium-high heat. Add in the onions, sprinkle with salt and saute until caramelized, stirring often, 25 to 30 minutes. Reserve.
Meanwhile, halve the fingerling potatoes
and toss in a bowl with olive oil, half of the thyme, the rosemary and half of the garlic
, and sprinkle with salt and pepper. Roast on a baking sheet at until golden brown, 25 to 30 minutes.
Toss the grape tomatoes
with olive oil
, salt, the sugar
, the remaining 2 sprigs thyme and half head garlic and drizzle
with balsamic vinegar
on a baking sheet until softened and beginning to char
, 15 to 20 minutes.
For the queso fundido: Increase the oven to 400 degrees F. Melt
the butter in a saucepot over medium heat, and then stir in the flour and cook, 2 minutes. Add the milk and cook until thickened, whisking occasionally, 8 minutes. Turn off the heat, add the cheeses and combine well. The mixture will be dough-like; it won't get oozy until it gets in the oven.
Transfer the mixture to a 10-inch cast-iron skillet or shallow baking dish
, and spread evenly. Bake 6 minutes, stir and bake another 6 minutes, then stir again. Put under the broiler until the cheese is browned in spots. Serve immediately with the dipping sides of the roasted poblanos, caramelized onions
, roasted fingerlings and tomatoes, gherkins, slices of baguette and dried sausage
Cook's Note: If you don't have a gas burner, you can char your poblanos under the broiler as well.