Note: this is my first homebrew attempt. Inspired by another homebrew entry on here called Way of the Emberfist, and based off of Way of the Sun Soul from Xanathar's Guide to Everything. The damage is changed from radiant to fire at a redcuced range and I have added 2 features, Emberfist, and Kindle the Blaze, adding Kindle Points to fuel subclass specific abilities. Any comments on refining it would be appreciated - I've no idea how to guage if this is overpowered or not.

Those who follow the Way of the Kindled Soul,  have an innate tie to the elemental plane of fire - in some form or another. The Monasteries are usually situated near doorways into the elemental plane and are often led by fire genasi or other beings from within that realm.
The purposes of these Monasteries vary, often they exist to guard the entrance - from both sides, as well as providing refuge to those touched by the plane and in need of assistance to live with it. For otherwise they may find themselves struggling with a power they cannot control.
Followers of the Kindled Soul work to deepen this connection within themselves; from a tenuous link to an internal fire, referred to as one's Blaze. Overtime as their ability grows, stoking the embers from mere kindling to a raging bonfire.
They learn to harness the Blaze within; incorporating aspects of it into their strikes, using its essence to absorb external flames, in time becoming tolerant of its consuming touch, even learning to project it outward. Eventually their Blaze physically manifests around them at all times.
When a Monk is admitted onto this path, they are adorned with enchanted tattoos depicting tendrils of flame. These respond to a Kindled Souls' Blaze and when accessing their abilities, glow as if aflame. One's tattoos grow in size and complexity as they continue along this Path.

Scorching Strike

Starting when you choose this tradition at 3rd level, you can hurl searing bolts of magical flames.

You gain a new attack option that you can use with the Attack action. This special attack is a ranged spell attack with a range of 15 feet. You are proficient with it, and you add your Dexterity modifier to its attack and damage rolls. Its damage is fire, and its damage die is a d4. This die changes as you gain monk levels, as shown in the Martial Arts column of the Monk table.

When you take the Attack action on your turn and use this special attack as part of it, you can spend 1 ki point to make the special attack twice as a bonus action.

When you gain the Extra Attack feature, this special attack can be used for any of the attacks you make as part of the Attack action.

Instead of a creature, you can target a flammable object or pile of objects that is not being worn or carried, and attempt to start a fire.  Make a Dexterity check.  The difficulty of the check will depend on whether the flammable object(s) are very flammable (oil, pitch, paper), moderately flammable (dry logs, coal), or not very flammable (wet wood, damp rags).

Kindle the Blaze

Starting at 3rd level, your affinity for the flame allows you to redirect it's power. Your ability to do this is represented by Kindled Points, the maximum of which you can store is 5. These Kindled Points may be used in place of Ki Points to fuel your Kindled Soul features: Emberfist, Blast of Flames, and Searing Comet.

You gain Kindled Point(s) by using your reaction when a source of fire damage would deal damage to you, in proportion to the amount of damage dealt - as if you were not resistant/immune - as shown in the table below.

Any Kindled Points you have stored are lost when you finish a short or long rest.

 

Fire Damage	Kindled Points Gained
1-10	1
11-20	2
21-30	3
31-40	4
41+	5

Emberfist

Starting at 3rd level, when you spend a ki point to use the Flurry of Blows class feature, you may spend an additional ki point to wreath your fists in flames.  For the rest of your turn, your unarmed melee attacks deal an additional monk damage die as fire damage. This die changes as you gain monk levels, as shown in the Martial Arts column of the Monk table.

Control the Flame

You harness the fire within, learning to tame a fraction of the power and extend that control outward. You gain the control flames cantrip.

Blast of Flames

At 6th level, you gain the ability to channel your ki into searing waves of energy. Immediately after you take the Attack action on your turn, you can spend 2 ki points to cast the burning hands spell as a bonus action.

You can spend additional ki points to cast burning hands as a higher-level spell. Each additional ki point you spend increases the spell’s level by 1. The maximum number of ki points (2 plus any additional points) that you can spend on the spell equals half your monk level.

Heat Tolerance

At 11th level, through constant exposure to fire the tips of your fingers blacken, as though they have been burned.

You now resist all fire damage. If you already possess fire resistance due to a racial trait, you are instead immune to fire damage.

Fire Immunity

If you have a racial trait granting fire resistance, Heat Tolerance now grants you fire damage immunity.

Fire Resistance

If you do not have a racial trait granting fire resistance, Heat Tolerance now grants you fire damage resistance.

Searing Comet

At 11th level, you gain the ability to create an orb of concentrated fire that erupts into a devastating explosion. As an action, you magically create an orb and hurl it at a point you choose within 150 feet, where it erupts for a brief but deadly instant.

Each creature in that 20-foot-radius sphere must succeed on a Constitution saving throw or take 2d6 fire damage.  If damage from this attack reduces a target to 0 hit points, that target and all it is wearing or carrying is reduced to fine black ash.

You can increase the sphere’s damage by spending ki points. Each point you spend, to a maximum of 3, increases the damage by 2d6.

Bonfire Within

 At 17th level, you become wreathed in spiraling flames. You shed bright light in a 30-foot radius and dim light for an additional 30 feet. You can extinguish or restore the flames as a bonus action.

If a creature hits you with a melee attack while this aura is active, you can use your reaction to deal fire damage to the creature. The fire damage equals 5 + your Wisdom modifier.

While this aura is active, you resist cold damage.