Rajas con Crema
Serves 4

4 fresh poblano chiles
1/2 white onion
2 tablespoons butter
1/4 cup milk
Kosher salt
1 tablespoon Mexican crema or creme fraiche
2 epazote leaves, chopped (optional)

1. Char the chiles over a gas flame or on a very hot grill until blackened. While still hot, wrap in paper towels to steam and cool. Remove the stem and seeds and rub off all the blackened skin and clinging seeds with the edge of a spoon or the paper towels. (Don't wash them; much of the flavor goes down the drain.) Don't worry if a little skin remains. If you want a milder taste, remove the ribs inside the chiles. Cut into lengthwise strips 3/4 inch wide.

2. Cut the onion into thin strips, from the stem to root instead of across (they hold their shape better this way).

3. Melt the butter over medium-low heat in a heavy frying pan and cook the onion and peppers together for 5 minutes, stirring often.

4. When the onion is softened, pour the milk over the vegetables and cook very slowly until it is evaporated. Season with salt to taste. (Can be made head to this point and refrigerated; reheat before serving.)

5. Just before serving, stir in the crema or creme fraiche and epazote, if using. Serve hot.