Simply selecting your full cap of ships and sending them over to another planet, possibly even using FRD if you want to be extra lazy.
I think the definition of blobbing is dependent on who you are. To some, it's simply a bunch of units against a smaller bunch of units. To others, it's the lack of micro in a bunch of units.
To me, "blobbing", is lack of tactics in favor of raw firepower. If you don't need to think and can just send your "blob" of ships against the enemy ships without any risk of losing anything significant, that is blobbing.
I agree with both of these definitions.
To actually expound upon Moonshine Fox's definition, some strategies even OPERATE simply by putting your entire army on FRD. Enclave Ships + Neinzul Ships can basically win the game this way.
The best strategy now (that I've encountered) is to take your entire blob, move it to the enemy planet, then fight until you start getting overwhelmed. Then you leave and since you've probably alerted everything on the planet, you can bait the whole enemy force into your turrets and crush them easily. That's not very exciting or strategic, since you can do it the same way every time. Eyes add a little more diversity, but that's basically another formula of sending your Raid Starships in to kill the Guard Posts, then going back to the first strategy.
My theory (keyword here is theory) is that the game would be a lot more interesting if you didn't WANT to wake up the entire enemy hornet's nest at once. And in fact, this is the way it used to be before it changed somewhere around 4.0ish. Something should encourage you to only send the necessary fleet to attack the planet, clearing out bits and pieces of its forces until you've removed most of the major threat, then you can send in your entire fleet.
A fun strategy that a lot of people miss is the "Beachhead" Strategy, which really isn't useful anymore except in a few rare situations. To bring back a scenario where you feared to awaken the whole enemy planet, Beachheads would become a lot more useful and ideal than they are now.
But then the question becomes, how do we punish the player for simply waking up the entire enemy planet? My answer is simply Guardians. I think Guardians in their current incarnation are rather boring and homogenized. Though they have cool and unique abilities, they basically only act as a force multiplier, and you deal with them all basically in the same way (blobbing), so they've lost a lot of their personality.
I think if you made EACH Guardian extremely powerful and difficult to deal with, the game would be so much more enjoyable and interesting. Instead of assaulting Guardians head-on, you'd have to fight around them, only activating each Guardian when you had the right counters in the right places. Activating a planet full of Guardians would spell disaster, as even bringing them into your defenses would bring swift defeat.
But how do you accomplish this? It's simple, you just take the Guardians in their current form, and buff the hell out of them. For example, to approach a Lightning Guardian with a swarm of units, you'd lose most of your army instantly. Instead, we give it the "Light" Hull Type and make it so that Frigates are intended to kill it from afar. You could approach a Flak Guardian with your whole army, but it'll eat smaller stuff alive, so instead send your Starships and it will do rather crappy damage so you can take it out. Sniper Guardians become long-range harbingers of death, so blobbing with one of these on the planet means you'll lose most of your army from a distance. Instead, send a group of Fighters to activate it and take it out.
Some Guardians would still require "blobbing", or using your whole force. For example, Vampire Guardians would literally steal so much health that with insufficient firepower you couldn't defeat them.
In other words, how you dealt with each individual planet completely depends on what fleet ships and Guardians on that planet. Each planet is a different and unique foe that depends on what Guardians and forces are there, and how you need to deal with them. Instead of most planets having 10-15 weak Guardians, most now would have maybe 2-3. But to activate them all at once (by sending your whole force) would spell disaster.
I think this makes the game a lot more interesting because every scenario, every planet is a different experience. There's no "best" way to deal with each planet. That highly depends on what units you have and what units they have. That's just my opinion though, some people seem fine with the current "send everything and retreat when necessary" mechanics, I just find it very grindy and formulaic.