By-products upcycling to produce ingredients has increased in the last years. However, the perception of foods with these ingredients must be studied to find the proper way to inform the consumer. The aim of this work was to study the purchase intention and healthiness and environmental friendliness perceptions of a flan dessert, enriched with orange juice by-product fibre. The effect of different product categories (ready-to-eat, powdered form, home-made type), fibre origin claim, and the addition of a sustainability logo in the packaging were studied through an online survey carried out in Spain (n = 342) and Uruguay (n = 307). Data were analyzed by PLS and cluster analysis. Both Spanish and Uruguayan participants considered the product category the most important attribute in purchase intention and in healthiness and environmental friendliness perception, being the home-made product preferred by both. Logo presence was more important for purchase intention and perceived environmental friendliness, while information about fibre origin was more important for healthiness perception. The home-made product with a logo and the claim about fibre origin was the one that had the highest perception of being healthy and environmentally friendly in both populations. Logo presence affected positively purchase intention for both groups, but the relative importance was higher in the case of Spanish consumers. The allegation “source of fibre” also increased healthiness and environmental friendliness perceptions, although not the purchase intention in Spain. Cluster analysis identified different groups of consumers on each country, who gave different relative importance to each attribute in purchase intention.