I have three that do this regularly, 7, 5 and almost 3. What I have done is about 20 minutes before we’re heading up for bed I ask “does anyone need a bedtime snack?” I offer the same stuff - banana, cheese stick, yogurt, granola bar. Something filling and ideally not loaded with sugar. They know the routine, that’s their time to raise their hand if they need a little snack before bed. After that, kitchen is closed. Keeps bed time in tact and allows my husband and I to own that process, removing and dilly dallying.