Time: 30 minutes. Karen Kadlec uses a slice of regular sharp cheddar and a slice of black pepper cheddar, but the second cheese isn't widely available. If you can find it, by all means try it, but then skip the final sprinkle of black pepper.
2 tablespoons softened butter, divided
1 teaspoon olive oil
1/3 cup diced (1/2-in.) zucchini
1/3 cup diced (1/2-in.) onion
1/3 cup diced (1/2-in.) mushrooms
2 teaspoons finely chopped tarragon
Freshly ground black pepper
4 slices sourdough bread
2 slices (1 oz.) each sharp cheddar and jack cheese
How to Make It
Melt 1 tsp. butter with oil in a large nonstick frying pan over medium heat. Cook vegetables, stirring, until barely tender, about 5 minutes. Stir in tarragon, season to taste with salt and pepper, and scoop out of pan into a bowl.
Butter 1 side of bread slices with remaining butter. Put 2 slices in pan, buttered side down, and top with cooked vegetables. Layer with cheeses and sprinkle with pepper to taste. Set remaining bread slices, buttered side up, on top. Cook sandwiches, turning once, until golden brown and cheese is melting, about 8 minutes.