Butter an 8-inch-square baking pan. Line with parchment or wax paper, letting edges of paper hang over sides of pan.

In a Pyrex measurin cup toss chopped chocolate and baking soda. Stir in butter, milk, salt and vanilla. No nuts yet. Microwave on 40% power for 20 seconds then stop and mix. Another 20, mix. Mixture should be heated as little as possible but smooth. Mix in nuts.

Scrape mixture into prepared pan. Refrigerate until set, about 4 hours or overnight. Lift fudge on paper out of pan and use a large knife to cut into squares.

Notes: This recipe has butter reduced to 3 tablespoons from 4. Also added the baking soda as suggested in Cooks Illust. as it gives it a firmer texture.

Last time make: For the chocolate I used 12 oz Nestles semi sweet chips, 2 oz dark bittersweet and 2 oz unsweetened. Pretty good. Try more unsweetened next time

Note: baking soda is an odd addition. According to Cooks Illustrated 15-minute fudge recipe, BAKING SODA: Increases the pH of the fudge and makes the texture firmer.