A couple of things you might need to know… I believe the the Arduino 101 still has some issues with BLE & Blynk right now, due to something on Intel’s end. Search this forum for Arduino 101 for more.
And while Blynk can use BLE/BT on other devices, it is still BETA like; It has some limitations on which Widgets are supported; And the App still needs internet access to the Server for login and project data, even if it doesn’t need internet for the MCU link.
Now, hopefully before all your hopes crash and burn 
There are a few BBQ/Smoker/Cooker projects, that are well detailed on this site, but might be using differing MCUs and thermostats. However, the basics will still apply.
Don’t search for the particular “sensor”, rather just the word BBQ, etc. For example:
If you really prefer to use what you have then I recommend getting it to work with basic Arduino code first, and learning some basics of Blynk on the side… Then it will be easier to merge the two later, as opposed to trying it cram it all together at once… particularly as that ET-732 sounds complicated enough to hack with Arduino as it is (based on some quick Google searches).