tomato pesto tarts

from "the cook's encyclopaedia of four ingredient cooking"

preheat oven to 425 degrees.
lightly grease a large cookie sheet and sprinkle it with water.
spread out puff pastry sheet onto a lightly floured surface
  and cut out whatever shape you wish to make your tarts (they
  recommend 4-6" rounds.  i made the whole thing in a square
  to get the most out of the dough as it came from the store).

transfer the pastry piece(s) to the cookie sheet.  using the tip
of a sharp knife, mark a shallow cut 1/2" from the edge of each
shape to form a rim.

take 2 TB (or more) of pesto (they recommend red which i couldn't
find, normal green or cilantro works too) and spread it on the
shape(s) inside the rim you made.  cut half of 1.5 pounds of 
cherry or plum or grape tomatos in half, and dump all the tomatos,
cut and uncut, into the shape(s) inside the rim.  season lightly
(i used salt/pepper).

bake for 10-12 minutes until the pastry starts to rise (they say
20, but i think that's way too much).  dot with remaining pesto
and spoon some chunks of mascarpone cheese (they recommend a
half cup, i recommend mooooore) evenly over the shape(s).  you
don't have to spread it, just distribute chunks.  it melts and
swims.  sprinkle a little more black pepper on.  bake for 10
more minutes or until golden brown.  serve warm.