Remove one sheet from the puff pastry box and thaw at room temperature for about 20-30 minutes. (Save other sheet for another use.) Heat oven to 400 degrees.
Rinse greens and drain in a colander so some water is still clinging to the leaves. Place greens in a microwave-safe, covered, vented container and micro cook for 8 minutes, stirring at the halfway point. Remove from oven and re-drain greens in colander, pressing with the back of a spoon to remove any excess water. When cool, place greens on a cutting board, gather together into a bunch and chop more finely.
While pastry is thawing and greens are cooking, in a large bowl mix feta, ricotta, green onions, eggs and 1/2 of a Cut 'N Clean Greens Seasoning packet (save rest for another use). Add cooled greens and stir until mixture is well combined. (This may be done in an electric mixer if you wish.)
On a floured board, unfold puff pastry; lightly flour the top of the pastry as well. When unfolded, the pastry will measure about 9.5 by 9 inches. With a rolling pin, roll it lengthwise to about 9.5 by 15 inches. Cut into 8 vertical slices and 9 horizontal slices, to make a total of 72 small pieces.
Place puff pastry pieces on an ungreased baking sheet and top with a teaspoonful of the greens filling. Bake for 12 minutes, remove from oven and use a spatula to remove pieces to a cooling rack. The filling should stretch to cover all 72 bites.
Makes 72 appetizer bites; allow for several per person.
Notes: These savory squares are airy and addictive. The Cut 'N Clean Greens Seasoning packet provides just the right amount of zippy flavor. Substitute Rainbow Chard for Euro Greens for a change, and micro cook for only 4 minutes. Filling can be made a day in advance.