ATM IVs of 1w expiries are just shy above 4%, and likely to pick up pace. Growing in snail's pace even in 3m tenors.

As a result, the delta neutral trading strategy in this case involves the buying of a theoretically underpriced OTM option (because the considerable disparity exists between ATM premiums and IVs as shown in the diagram) while taking an opposite position in EURCHF options. 

Well, thereby, a common question pops up after this explanation, "How do I know if an option is theoretically underpriced?" I prefer to use Option Greeks platform that provides this information. 

EURCHF ATM put are trading at 31.48% more than Net Present Value.

Comparing reasonable delta contents, ATM IVs  and option premiums with net present values of such premiums, will give you the theoretical price of an option. 

Here, the implied volatilities of ATM contracts are just above at 6% for next 3 months tenors.

So if anyone anticipates it can still be possible to extract returns from this nerdy  volatility scene from this pair, even though exhausted bulls who think long lasting non-stop streak of bull run to take halt at this point. Yes, that's quite achievable from iron butterfly strategy.

To execute this strategy, the option trader assumes long on a lower strike Out-Of-The-Money put and shorts At-The-Money Put simultaneously short again on At-The-Money call and long on Out-Of-The-Money call, this results in a net credit to put on the trade. 

At Spot ref: 1.1087, iron butterfly strategy (EUR/CHF) can be executed as shown below,

Long 2M (1%) OTM -0.27 delta Put & Short ATM Put with positive theta or closer to zero + Short ATM Call with positive theta or closer to zero again & Long 2M (1%) OTM 0.27 delta call.

In iron butterfly, there is high probability of deriving certain yields as it contains both bull call and bear put spreads, hence it would likely yield variant payoffs from classic butterfly spreads.