Not sure how long you're riding but I ride very early on week days and for me those are usually 1-2hr workouts on the bike. I don't eat anything.

For longer rides, I try to eat an hour before my ride starts. If I'll be riding at a casual pace, I might eat a little closer to my ride start, I can finish digesting on the early part of the ride.

Before a race, I eat 2-3 hours before start time. My races are typically in the morning and I get up very early those days anyway.

It doesn't take much- all you really need to do is replace liver glycogen that was used over night. Around 250 cal of something carbohydrate heavy, in theory without much fiber. But in reality, I eat whatever carb-heavy thing appeals to me, fiber or not. Fat and protein will slow digestion, so I try to keep those macronutrients to a minimum if I'm needing to ride hard after eating.