Preheat oven to 350 degrees.

Combine the diced rhubarb with the 3 T. Sugar and Cinnamon and set aside for about 10 minutes to dissolve the sugar and bring out the juices from the rhubarb.

Then spread the rhubarb mixture into the bottom of a 9 inch cast iron skillet or an 8x8 baking dish or a 9 inch pie pan.

Roast that mixture for 15-20 minutes until the rhubarb is soft and the juices are bubbling.

Then ALLOW TO COOL until the mixture is just warm to the touch.

Then whisk together the Eggs, 1/2 Cup of Sugar and Vanilla.

Next, whisk in the Milk.

Then whisk in Flour, Lemon Zest and Salt. (This mixture must be vigorously whisked to insure no flour lumps. If you're concerned about that just add the flour from a sifter or pressed through a strainer to make sure no flour clumps will remain in the batter.) This mixture can be prepared up to 30 minutes ahead of time, according to the website The Kitchn.

Pour the batter over the roasted rhubarb mixture and bake for 35-40 minutes at 350 degrees. Bake until toothpick inserted in center comes out clean. Clafouti will puff up but will collapse once it begins to cool.

Serve warm for a custard like dessert, or for a firmer dessert it can be served at room temperature or even cold from the refrigerator.

Dust with Powdered Sugar if desired.