Line an 8x8- or 9x9-inch pan with foil, leaving enough foil overhang to lift the fudge out later; set pan aside.
In a heavy-bottomed saucepan over low heat, combine the 114 ounce can sweetened condensed milk, 3 cups white chocolate chips, and a pinch of salt.
Heat gently, stirring constantly, until the white chocolate chips are fully melted and the mixture is smooth and homogenous. Remove the pan from the heat.
Stir in 1 and 1/2 tsp McCormick Vanilla Extract and 1/2–2 tsp McCormick Peppermint Extract (start with 1/2 tsp and add up to 2 tsp to taste). The mixture will be thick.
Fold in 1 and 1/2 cups chopped up chocolate sandwich cookies until they are evenly distributed.
Scoop or spread the mixture into the prepared foil-lined pan and press it into an even layer with a spatula or the back of a spoon. If using, sprinkle 1/4 cup crushed candy canes evenly over the top and press lightly so they adhere.
Refrigerate the pan for at least 2 hours, or until the fudge is firm.
When set, use the foil overhang to lift the fudge from the pan, peel back the foil, and cut the fudge into squares.
Store the fudge covered at room temperature, or keep it refrigerated for up to one week.