I've been around hiring processes long enough to know that when you ask average questions you get average hires. So I am always on the lookout for provocative interview questions which help you learn much more about the person than just their canned answer to "their biggest weakness."

That's why I was excited to hear Olaf Mathe, co-founder and CEO of Mixmax, a company that builds a popular email extension, talk about his favorite interview questions on "The Twenty Minute VC Podcast."

Here are his three essential questions:

1. What offer could your current company make that would have you stay?

I love this question because it's so provocative. If a potential senior hire has gotten so far as to talk with the CEO, she is probably someone the company wants. So why would he see if he could get her to stay at her current company?

It's all about the ability to have tough conversations. Does this executive have the courage to go to her current CEO and talk about what's not working? Is she willing to confront difficult truths? Is this potential leader able to handle an open dialogue about what's working and not working about her current situation and explore what is possibly an awkward discussion about not joining your team after all?

Mixmax is not the only company who tries to talk new employees out of staying. Zappos famously pays new employees to leave after the first month. The point of this is to make sure they really want to be there.  

You're going to want this new executive to be around for a long time - hiring mistakes are costly. Make sure she really wants to be there and is the kind of person who has the guts for straight talk.

2. What area of professional development are you working on most deliberately and how?

"Learning" is the new "expertise." In a VUCA world (VUCA stands for volatility, uncertainty, complexity, ambiguity) where the only ones who survive are the ones who adapt, you have to have a learning organization. The only way to have a learning organization is to hire people who have learning embedded in their core. They don't develop themselves because the boss told them to. They are focused on their professional development because that's just what they do.

Asking a potential executive what his development goals simply shows you how important learning is to him. If he struggles to answer you'll know that he doesn't focus on building his skills. If he describes his learning goal as something that will make him look good ("I work too hard; I'm trying to learn to relax more and not come into the office seven days a week.") you'll know that his inclination is to position himself rather than genuinely work to improve himself.

If his answer, however, indicates a genuine focus on learning, then not only will it be a good data point it will also spark a deeper discussion. For example, I met with a new client recently, the CTO of a fin-tech startup. I asked him what he was working on as his own development goals. "I'm working on being a better presenter," he told me. "Not just my public speaking skills. I'm working on connecting more with my audience, whether it's one-on-one or a large room or somewhere in between. I guess you could say I'm working on my presence." I could see from his answer that this was someone who was investing in his own personal growth to be a better executive and leader.

Increasingly, winning comes from a culture of "learn-it-all" rather than "know-it all," to quote Satya Nardella, CEO of Microsoft. And, a culture of learning comes from the top, so make sure you check for this quality as you hire your senior executives.

3. Tell me about a project that failed and what, in retrospect, you could have done to get it back on track?

It's critical to hire executives who are reflective, who will step back and think about what worked and didn't work to help the team improve. This question is a way to assess that.

More deeply, debriefing projects and initiatives is an important way to continuously improve operational excellence. Is that something this person naturally does?

Finally, this question gets at the person's attitude about blame. Is this candidate able to look at a past failures and thoughtfully take responsibility without blaming others? That's the kind of executive who will help you build a strong culture alongside driving operational excellence.                 

Ask these questions next time you are hiring senior executives and see what kinds of conversations they spark.