You touch a piece of natural scenery - either a rock face/boulder or a tree to create a 3' x 6' door that leads to a pocket dimension. A total of five medium sized persons can enter, chosen by the caster. The atmosphere in the grotto is comfortable and dry, regardless of the weather outside.
Tree The tree spawns a 3' x 6' door that only those chosen by the spell caster can see. the door opens into a 100 square foot chamber (10' x 10') with rustic wooden furniture and furnishings related to the tree type. A magical fireplace provides warmth without smoke. A trap door in the floor, with a ladder, leads to a 50 square foot additional space.
Rock The door opens to a 150 square foot space resembling a cavern. A fire place sits in the center of the cavern, around which are bed rolls/sleeping spaces and chests.
The door is barely distinguishable from the underlying tree or rock, and when closed can be covered with an illusion to avoid detection (perception or investigation DC 19 to detect). The dimension space can be dark or dimly lit according to the caster's command. From inside the door is transparent, although it is opaque from the outside. Items left in the dimensional space can either be expelled or stored until the spell is recast. Living beings and magical items are expelled at the end of the spell. Modifications made to the interior of the dimensional space are retained between castings.
If cast at a higher level:
5th level An additional 80 square feet of space are added as well as capacity for an additional person, for each additional spell level. A tiny insect-like fey can also be summoned to guard the doorway.
Grotto Bug Tiny fey, unaligned AC: 8 Hp: 1 Speed 30 (walk, swim, climb, fly) STR 1 (-5) DEX 5 (-3) CON 8 (-1) INT 18 (+4) WIS 13 (+1) CHA 13 (+1)
Immune to charm; Truesight 60'; Passive perception 21. Cannot talk but understands common and sylvan.
7th level On casting creates food equivalent to the Heroes Feast spell
8th level The effects of charm spells are negated on those within and the dimensional space doubles the effect of healing magic and potions.
9th level The caster can grant the effects of Greater restoration on one person per day.
Magic cannot be used to access the inter-dimensional space, but the door can be attacked (AC16; 80hp; siege weapons do double damage). Spells cannot be cast through the door.
The grotto can be made permanent if the spell is cast every day with the same layout, for a year.
* - (A rock or tree large enough to accommodate a 6' x 3' door)