For stunning jelly desserts, patience is essential. That’s something Thu Buser, a Brooklyn-based chef and culinary artist, learned at an early age as she watched her mother spend hours on batches of rau câu, a Vietnamese dessert made with delicate, colorful layers of jelly. Now Buser crafts her own highly stylized jellied desserts, multicolored riffs on the rau câu she grew up eating. She injects fruit juices into perfectly clear jelly to create blooms of color and flavor: a kaleidoscope of electric green coconut-pandan, a sunset of yellow yuzu-lychee, a riot of fuchsia coconut-ube. “I can make any flavor pretty,” Buser says. Her syringe is her paintbrush, striking the cooling agar-based gelatin with delicate sweeps and precise staccato jabs. All of this is done effectively blind, since the injections are made from the bottom of the mold. The resulting florals within are transportive, a dome-shaped portal into worlds both alien and familiar.…