Stupid question alert!

Good answer from Lietchi.

A heart rate monitor may estimate more calories for a continuous hour, but separate half hours at the same intensity will burn about the same number of calories as a continuous hour. (Heart rate drifts upward during longer workouts for reasons that aren't related to calorie burn, but a heart-rate-based calorie estimator may be misled.)

She's also right that doing two separate sessions may allow the 2nd half hour to be a little more intense than it would've been if it immediately followed the first half hour, and higher intensity will burn more calories.

IMO, the continuous hour will have more positive effect on your endurance, loosely because we get better at the things we train for. If you want more endurance, it's not that every workout needs to be longer . . . but you'll get better endurance results if some workouts are longer. (From a general fitness perspective, it can be good to get a mix of intensities, like shorter/harder sessions, longer/easier sessions, some intervals, etc. But that ideally happens after you've gotten a reasonable cardiovascular base by mostly sticking with mildly challenging steady-state workout for a while as a beginner.)

Here's the thing, though: The best workouts are the ones that you find fun (at least reasonably/relatively fun), and that fit into your overall life in a practical way. What's theoretically "best", or burns the most calories - that's secondary.

Why? Because things we enjoy and that fit into our lives in an easy, natural, practical way are things that we're likely to keep doing on a regular basis because we want to do them.

By contrast, things that are difficult, need constant "motivation" in order happen, that leave us fatigued or burned out for the rest of our day(s) . . . those are going to procrastinate or skip with the slightest excuse, and they're to drop out of the picture entirely when other parts of life get a little complicated.

Exercise we do, even if theoretically less beneficial, burns 100% more calories and improves fitness commensurately more than exercise we don't do, y'know?

If you structure those enjoyable workouts so that there's always just a manageable bit of challenge, you'll also make fitness progress. (Challenging current capabilities creates fitness adaptation. Keeping the challenge manageable allows you to recover, adapt, and keep going.) Your variables are intensity (pace or terrain/resistance for biking), duration, frequency, and type of exercise. Change any of those to create more challenge (ideally not all of them at once, and ideally just a bit as what you're previously doing gets easier).

You're doing great!

There are no stupid questions....

All other things being equal you would expend a similar number of calories whether it's in one 60 minute session or split up into shorter rides and I agree that you may actually be able to ride at a higher intensity by splitting them up which would also be good.