1. Cut off the stem of the artichoke using a sharp sturdy knife like a chef knife.
2. Pull off the exterior leaves one by one until the heart becomes visible. Be careful not to get poked by a thorn.
3. Once the heart is visible, cut the top of the artichoke off by first locating the top of the heart (this is simply done by feeling the artichoke--starting at the bottom of the artichoke and feeling progressively upwards. The heart will feel hard; where there is no heart, the leaves will feel noticeably soft). Cut through the leaves at the top of the artichoke using a sharp sturdy knife. Cook in boiling, salted water until the hearts are tender.
4. Combine artichoke hearts, non-fat plain yogurt, grated parmesan cheese and frozen crabmeat and mix them well.
5. Spoon into a lightly greased 1 1/2 quart casserole.
6. Top with panko.
7. Bake at 325 for 15 to 20 minutes.
8. Serve with crackers or french bread.