What is it? Cream, the fatty top layer of whole milk, is churned until fat solids separate. By law, butter must contain at least 80% milk fat; artisanal versions may have more. May be salted and cultured.
Baking: Fat coats flour proteins and holds air bubbles produced by leaveners to create a tender texture. Also key for browning.
100 calories, 11g fat (7g sat, 0g trans) per tablespoon
What is it? Forcing hydrogen through vegetable oils makes margarine solid at room temp but also produces trans fats. Check ingredients; many margarines still use these hydrogenated oils. Others, like Smart Balance, now blend trans-fat-free palm oils with emulsified vegetable oils.
Baking: Stick margarines with 80% fat content work like butter, but spreadable styles won't hold form when baking.
100 calories, 11g fat (2—4g sat, 0g—2.5g trans) per tablespoon
EUROPEAN & ARTISANAL BUTTER
What is it? European versions can contain up to 90% milk fat, which may result in an extra gram of sat fat. Sold in 1- or ½-pound blocks, versus U.S. sticks. Also may or may not be salted.
Baking: No different from regular, though refined palates may detect extra richness. Many are also cultured, which adds subtle depth.
100 calories, 11g fat (7—8g sat, 0g trans) per tablespoon
What is it? Simply butter with air beaten into it. Fat savings vary between brands, from 30% to 50%. Available salted or plain.
Baking: With less fat, whipped butter cannot be substituted precisely in baking. Use as a spread only.
50—70 calories, 6—7g fat (3.5—5g sat, 0g trans) per tablespoon
What is it? Most start with ordinary butter, then replace some of the fat with water, starches, gelatins, or emulsifiers. Most also include salt to balance flavor.
Baking: Higher moisture impairs leavening and browning. Another one to use as a spread.
50—80 calories, 6—8g fat (2.5—5g sat, 0g trans) per tablespoon