3 cups (18 ounces) bittersweet or semisweet chocolate chips
1/2 teaspoon (scant) peppermint extract
18 large marshmallows, snipped in half lengthwise
8 square matzahs, each broken into ½ inch pieces
Line 9 x 5-inch loaf pan with foil, extending foil over sides of pan. Melt chocolate in microwave-safe bowl until smooth and warm to touch, stopping occasionally to stir, 2 to 3 minutes. Mix in peppermint extract.
Spread 1/2 cup warm chocolate in pan or tilt pan to allow chocolate to spread evenly. Sprinkle half of marshmallows and half of matzah pieces over. Pour remaining chocolate over, reserving 1 tablespoon chocolate in bowl. Top with marshmallows and matzahs, pressing to partially submerge. Using spoon, drizzle reserved chocolate in bowl over marshmallows in zigzag lines. Freeze until firm enough to cut, about 30 minutes.
Using foil as aid, lift chocolate out of pan. Peel foil off chocolate. Cut into 21 squares. Store chilled in airtight container.