Dairy-free margarines or oils. You can also use dairy-free or soy margarine, coconut oil, shortening, and olive or canola oil for part or all of the butter.
You may be able to tolerate some cow's milk yogurts, because they have very little lactose. Choose ones with live, active bacterial cultures for the least amount of lactose.
If you can't tolerate regular yogurt, try soy or coconut milk yogurts, soy sour cream, or unsweetened fruit puree.
Sour Cream Substitutes
Let soy based or lactose-free sour creams serve as subs in your favorite recipes. Pureed silken tofu and plain soy yogurt can also work well.
Aged cheeses such as cheddar, Colby, Parmesan, and Swiss have very little lactose, only about 0.1 gram per ounce. American cheese, cream cheese, and cottage cheese are also low in lactose.
You can use hemp, rice, reduced lactose, lactose-free, or soy cheese in recipes to replace cheese.
Ice Cream Substitutes
There is a wide variety of diary-free ice creams and frozen yogurts made from soy, rice, hemp, coconut, and lactose-free milks.
Sorbet, made from fruit, sugar, and water, is another option.
Sherbet is made with milk but only contains a small amount of lactose, about 4-6 grams per cup.
Most dark chocolate is lactose-free and comes in a wide variety of shapes and sweetness levels. Check the label to be sure it doesn't contain any dairy ingredients.
Carob chips and rice milk chocolate are two options for chocolate made with cow's milk.