Preheat oven to 425 degrees F (220 degrees C).
Cut Poblano Pepper (1) pepper in half lengthwise; remove stems and seeds. Place cut sides down on a foil-lined baking sheet.
Roast 20 to 25 minutes or until tender. Wrap in foil. When cool enough to handle, peel and discard skin. Cut roasted pepper into strips.
If desired, sprinkle cut sides of Peach (2) halves with the Ancho Chili Powder (1/2 teaspoon). Using a potato masher or the flat side of a meat mallet, gently smash peach halves to 1/2-inch thickness.
Top two of the Sourdough Bread (4 slice) with Sharp White Cheddar Cheese (3 ounce). Add two peach halves, poblano strips, and Bacon (4 slice) to each. Top with remaining bread slices. Spread Butter (2 tablespoon) both sides of each sandwich.
Cook sandwiches in a hot skillet over medium heat for 3 to 5 minutes or until toasted. Turn; repeat on other side until cheese melts. Serve immediately.