The Ethereal Step conclave ability of a Horizon Walker Ranger is described as such:
At 7th level, you learn to step through the Ethereal Plane. As a bonus action on your turn, you can cast the Etherealness spell with this feature, without expending a spell slot, but the spell ends at the end of the current turn.
And Etherealness is a 7th level spell, with the following included in the description (Emphasis mine):
At Higher Levels. When you cast this spell using a spell slot of 8th level or higher, you can target up to three willing creatures (including you) for each slot level above 7th. The creatures must be within 10 feet of you when you cast the spell.
My question is: does this mean that the spell will always be cast at the 7th level anytime this ability is used, or is there something that can be done to cast it at a higher level? I'm currently playing in a party with 2 other player characters, and an ability that could transport the 3 of us together this way would be very useful.
Thanks for the responses.