I'm thinking taffy.

Depends on the exact composition but most lavas are going to be way more viscous than honey.
- Does "very thick" mean nothing to you?
- So... Treacle?
  
  Ohh, wow, you solved a long-standing mystery to me! I've been listening to a lot of discworld novels and could not figure out what "treacle mine road" was supposed to translate to. Now that I know the spelling I could finally look it up. Thanks! ❤️

You can eat anything once. If your brave enough.
- When does something count as being eaten - once you swallow it? I don't think you'd succeed at that with lava.
  
  You'd be able to taste it which I think would fulfill the requirements of knowing its texture.
- Just shove an insulated hose through your esophagus and out your bunhole and pass lava through it
  
  Holy mackerel
- In fact, lava is so nutritious it will fill you up for the rest of your life!

I've had it in cake form. Pretty good.
- I choose to believe you're taking about having pica, not eating a molten chocolate cake.
  
  you're missing out

The viscosity of most lava is about that of ketchup, roughly 10,000 to 100,000 times that of water
https://en.m.wikipedia.org/wiki/Lava#%3A%7E%3Atext=The+viscosity+of+most+lava%2C100%2C000+times+that+of+water.
- Alright so I got curious. For the non people-who-know-what-viscosity-is-measured-in people out there, viscosity is measured in centipoise, which is 1/100 poise. Water is 1 centipoise, hence why we use centipoise over poise. Don't ask me any more than that because I have no idea what I'm talking about.
  Lava is anywhere between 10,000 - 1,000,000 cP. According to this chart, there are many edible things that fall within that viscosity. Now lava is very hot, so if we're going to simulate the experience of eating lava in a safe way with edible ingredients, we need something that is that viscous at high temperatures. This page (PDF warning) says that 140f (60c) is the highest temp food can be without burning you immediately.
  There isn't much on the above chart that is both edible and has its viscosity measured around those temps. The most promising one was chocolate, which is about 25,000 cP. But it doesn't have a temperature listed. According to lived experience and my ass, melted chocolate has a pretty consistent viscosity at various temperatures, making it a suitable stand in for molten lava.
  However, viscosity isn't the end all be all of a lava eating experience. Lava is rocks and rocks are dense. Lava also looks like it would be sticky. Unfortunately, I couldn't find anything on the chart that matches the density of lava that is still edible (2600-2800 kg/m^3 for those who were curious). And there is also no unit of measurement for stickiness. But google tells me that some lava is sticky like peanut butter. So our edible lava needs to be considerably dense (thus, chewy) and sticky.
  With these things in mind (viscosity, chewiness, and stickiness), I think the best edible stand ins for molten lava would be hot peanut butter (250,000 cP), with honorable mentions being rice pudding (10,000 cP @100C), and hot toothpaste (70,000 cP @40C). Color them bright orange and maybe throw in some Carolina reaper for authenticity and baby you've got some edible lava going
  
  hot orange toothpaste with carolina reaper? michelin star
  
  That seems suspiciously low viscosity. When we see lava running down a volcano it's already cooling down, and is much more viscous. I think that's the image OP has in mind when thinking of honey. Lava with the viscosity of warm chocolate would be lava fresh out of a volcano.
  
  Delicious comment
  
  now is that kinematic or dynamic viscosity?

And it’s quite heavy, being rock and all. So imagine very weighty honey.
- Yeah. You know all those is movies and stuff where people sink in lava?
  Nope. It's too dense. You'd be so buoyant you'd just stay on top.
  
  Who you calling buoyant?
  
  Hey, asshole, don't you tell me how dense I am, I'm an AMERICAN
  jumps into lava for freedom and sinks
  
  I always thought that it just looks like they sink because their bodies are instantly vaporized at the point where they meet the lava.
  
  I must not watch the right things, I don't recall ever seeing media of a person sinking in lava. The closest was the Terminator being immersed in molten metal, but he was probably more dense than the molten metal being made of room temperature metal

Ice is a mineral. Thus, water is lava. Hence, you eat lava every day, and it is not the texture of thick honey. QED.

It most definitely has a satisfying snap when you break the surface tension of a nice steamy blob. Maybe similar to a warm Mozzarella.
- New headcanon is lava has the consistency of cheese sticks

I imagine it tastes like sand but spicy
- Gotta taste pretty sulfurous right?

Lava is rocks. Liquid rocks is still rocks.
- Yeah but salt is rocks and that stuff is delicious
- Yeah, but since it's a liquid it doesn't have the texture of solid rock.

mmm forbidden spicy honey

'a'ā or pāhoehoe?
- It's gotta be pahoehoe (the one that looks like honey being stirred)
- 'a'ā looks like it would fizz like pop rocks.
- Imagine the terminology if instead of it coming from the study of the Hawaiian volcano system, it came from the Icelandic one.
  Then we'd be memorizing words like herliaphongoffjlyur.