A few hours before making sandwiches, place whole packages of Honey or Cinnamon Grahams in their original packaging into freezer. Frozen graham crackers will be less likely to crack when sandwiches are gently squeezed together.
TO MAKE ONE LARGE SLAB OF ICE CREAM: Take ice cream out of freezer and allow to soften for about 5 minutes. Line rimmed baking pan that fits in your freezer with plastic wrap, with extra hanging over sides of pan. You will use extra plastic to lift sheet of ice cream out of pan later.
Use large knife to cut ice cream into equal 1 to 1 ½-inch-thick slabs. Lay slabs flat, pressed together, side by side in pan. Use rubber spatula to smooth ice cream slabs, getting rid of seams until you have one continuous 1 to 1 ½-inch-thick sheet of ice cream in pan. Cover ice cream with plastic wrap and return to freezer to firm up.
TO ASSEMBLE SANDWICHES: Remove ice cream from freezer. Unwrap top layer of plastic wrap from ice cream. Grab edges of bottom plastic to lift whole ice cream sheet from pan and put it on cutting surface.
Remove Grahams from freezer and take crackers out of packaging. Lay Grahams face up side by side in straight lines to cover top of ice cream. Keep extra Grahams nearby for other side of sandwiches.
With sharp knife, cut around edges of Grahams through layer of ice cream, forming individual squares.
Working quickly, peel end square of ice cream off plastic wrap, add second cracker to back to make sandwich, and squeeze them gently together. Place sandwich back on sheet pan that previously held ice cream. Continue until all sandwiches are made.
Put pan back in freezer. Refreeze sandwiches for at least 15 minutes to firm up before serving. If not serving them that day, wrap each sandwich individually in plastic wrap or waxed paper, and return to freezer until ready to eat.
NOTE: You can efficiently make two different flavors of sandwiches at the same time simply by filling each half of pan with a different flavor of ice cream. Or instead of single-flavored sandwiches, you can cut thinner slabs of two ice cream flavors and layer them on top of each other in pan before smoothing as directed.
To make just one or two sandwiches, place scoop of softened ice cream between two Grahams, and gently press together. Place in freezer until ice cream sets up. If you want neat edges, cut off excess ice cream with sharp knife and enjoy.
VARIATION: To add nuts or jimmies, place toppings in small bowl. After sandwiches have been assembled and are still soft, dip them into toppings to coat exposed ice cream edges. Refreeze, serve, and store as directed above.
To make chocolate-dipped sandwiches, sandwiches must be frozen hard first. Melt chocolate chips with ½ to 1 teaspoon of oil and stir completely. Dip sandwich—just one corner triangle or half the sandwich gives a great look—into melted chocolate and lay sandwich on sheet pan. Refreeze, serve, and store as directed above.