• Strip the chard leaves from the stems, by hand or with a knife. If the stems are wide, cut them lengthwise about ½-inch thick. Chop the stems into pieces about ¼-inch thick. Roughly cut the leaves into 2-inch pieces. (They can still be wet from washing.)
• Soften and plump the raisins in a small bowl with some water.
• Heat the olive oil a medium skillet on medium flame. Add the chard stems and cook about 5 minutes. Stir in the garlic. Add the chard leaves and sprinkle with salt. Cover the pan and cook until the leaves are very soft, 6 to 8 minutes. Remove the cover and cook, stirring occasionally, until most of the extra liquid evaporates and the leaves have seriously shrunk. Splash the pan with the vinegar and season with salt to taste.

Avocado Crema:

• Puree everything together in a blender. 

Assemble the quesadillas:

• Lightly brush one side of a tortilla with olive oil. Place oil side down in a skillet.  Sprinkle evenly with a quarter of the cheese. Scatter half of the chard over the cheese.
• Drain the raisins, distribute half of them evenly over the cheese and chard. Sprinkle with another quarter of the. Top with a tortilla and brush lightly with olive oil. Cook until the bottoms are golden, 3 or 4 minutes. Gently press down the top with a spatula. Gently flip the quesadilla over to brown the other side. Keep warm and repeat to make the second tortilla. (You can use 2 skillets and make both quesadillas at the same time.
• Transfer to a cutting board. Cut each tortilla into 8 wedges. (If you let the quesadillas cool a few minutes they will be easier to cut. Serve with Avocado Crema or a favorite salsa.