The first thing you have to do is, make sure none of them strips are bent, twisted, crooked, bowed, warped, etc. I would build it using 1 X 2 strips. If you want 24 inches wide, then you'll need 24 sticks. Run every stick through a planer until the proper thickness is achieved, then through a jointer until proper height is achieved. If the sticks are not the same length, don't worry about it, you'll cut your desired shape once all the strips are glued and and set.
Now is where the the decision making comes in. You can just glue all the joints together and clamp. Or you can drill for dowels, glue and clamp. Or you can cut slots and use biscuits, glue and clamp. My personal preference is to dowel. I have a block that I use pretty regularly that is just glued. I built it over 20 years ago. So gluing alone is not without it's merits. Just be sure, no matter what you do, to get a GOOD water proof wood glue.
There are 2 ways to use dowels. You can drill holes at different intervals and use short dowels, or you can drill all the strips in the same location and use dowels the width of the block. Either way, you need a drill press and a guide of some sort so you drill ALL the holes exactly where they need to be. This is easily achieved with a biscuit cutter, because the cutter has a built in guide, or fence if you will. Dowels and biscuits would just help prevent one or more of the strips from warping. If using dowels, long ones placed every 6 inches is more than sufficient.
Are all the strips the same shade? If not, alternate different shades. It looks cool.
Since you will be working with a lot of strips, I'd glue 6 or 10, clamp and leave them for 24 hours. Then do another 6 or 10 to the ones you've already glued, and leave for 24 hours. Go that way until all are glued and set. Then leave the whole thing clamped good and tight for a week.
Building it the way I've laid out is overkill. But you'll never have to replace it. It will last your lifetime and probably several generations more.
Once everything is dry and cured, You can trim to final shape (I would use a band saw) and decide if you want to trim, or router the edges or leave it. I would router the top edge with a cove or round over bit. Once your edge treatment is done you will need to run the whole thing through a planer again. If the planer won't accommodate a chunk this size, you have to belt sand at least the top to make sure everything is perfectly flat and the excess glue is gone. Then finish sand. I wouldn't apply anything but a food grade oil (i.e. olive, vegetable, peanut) of your liking to the board. Just rub it in with a paper towel.
If you need anymore, or I've missed something, let me know.
