What's some ways to reciprocate kindness to a man I'm not in a relationship with but whom I'm interested in/vetting? Oh the guys my boss.

Recent new job and I now work for this man. I knew him before although not super well. I applied for the job because I was interested in getting to know him better and he had previously shown some interest in me. Works actually a pretty good environment for me to get to know a person as I can get shy and awkward around romantic interests but a few of my personal traits shine when working. Romance potential aside the job is really good for my career goals and is just a good low stress job with good hours for my work/life balance. I want to stay in the friendly flirty stage for a few weeks at least to work out if I want to pursue him as a relationship interest or keep it professional. I figured it gives him a chance to do the same. What I've learnt about him so far is impressing me, but I also know once the new wears off you get to better see who a person is.

He's been kind, thoughtful and obviously cares about what I think about him. How should I reciprocate this? He is also flirty without making it awkward, but the workplace in general is like that. He's definitely the leader who makes good decisions and that's making it easy for me even just work wise.

For context cause I know the boss employee dynamic may trigger some people. I'm 29 and he is slightly younger then me. He aren't stupid he most likely suspects my intentions. And I know the risks involved and have backup plans. I'm not finacially dependent on this job.

If you want to brainstorm with me his valve as husband potential feel free to PM me just I don't want to post too many identifying details here