Margarine, along with butter, is listed as a typical roll-in fat for laminated croissant dough.
During lamination, the roll-in fat is spread between sheets of dough and preserved through repeated rolling and folding. Those fat layers act as barriers between dough layers. In the oven, water turns to steam and helps separate the layers, producing the croissant’s flaky lift.
Butter is traditional and prized for flavor, but it has a relatively low melting point of about 32°C. That makes temperature control important: butter can soften or leak during sheeting, fermentation, and folding. Specialized margarine can be formulated with a higher melting point and suitable plasticity, making it easier to handle in commercial production.
Margarine does not mean the dough is no longer a croissant. It is a practical alternative roll-in fat, especially in industrial baking. The key distinction is between roll-in fat, which creates the layers, and in-dough fat, which contributes mainly to softness and dough texture.