The Gaufre Liégeoise Garnie is a Liège waffle loaded with ice cream or other fillings, and the bread is denser and sweeter than an ordinary waffle, which changes everything about how it carries a filling. The Liège waffle is made from an enriched yeasted dough rather than a thin batter, with pearl sugar worked through it so the sugar caramelizes on the iron into hard, crunchy pockets. The result is heavier, chewier, and sweeter than a standard gaufre, with a surface that goes lacquered rather than just crisp. Filled or topped, often with ice cream, it is eaten in the hand, which keeps it in the same sandwich logic as the folded galette: a cooked bread holding a soft filling, no plate.
The density is the craft. A light waffle would collapse under a scoop of ice cream and a heap of cream; the Liège dough is structurally stout enough to take the weight and the cold without going to mush in the first minute. Its built-in sweetness and caramelized sugar mean it does not need much help, so the filling tends to contrast in temperature rather than pile on flavor: cold ice cream against the dense, warm, sugar-crackled dough, the meltwater soaking only slowly into a crumb tight enough to resist it. It still has a short window. The contrast is best while the waffle is warm and the ice cream cold, so it is stall and fairground food, handed over on paper and eaten where you stand.
This is a France and Belgium tradition that straddles the border, and it is the heaviest member of the waffle-as-sandwich set: the one whose bread is rich enough to be half the dish. The variations build on the same dense base by changing what tops it, ice cream in one version, fruit and cream in another, the lighter batter waffle as its own separate base. Those relatives, the loaded waffles eaten like sandwiches alongside the buckwheat galettes and wheat-flour crêpes of the same hot-iron tradition, are gathered under Crêpe & Galette Salée, and the Gaufre Liégeoise Garnie is its sturdiest, sweetest member.