Preheat oven to 350 and grease a 10-cup bundt pan and lightly flour.
In small bowl toss the rhubarb and the three tablespoons of sugar and a tiny sprinkle of lemon juice (if you have it - if you don't it is NO BIG DEAL, I like acid with my fruit but it is def not necessary and it is not a measurable amount so it is not even in the ingredient list).
In the large bowl of an electric mixer beat together the eggs, oil and sugar for about seven minutes with the paddle attachment - it will get nice and large and fluffy.
In a separate bowl mix whisk together the flour, salt, and baking soda.
Add the dry ingredients, alternating with the buttermilk into the egg and oil mixture mixing until just combined. Make sure not to over mix it.
Bake in the middle of the oven for about 45 minutes or until a toothpick inserted comes out clean. Cool the cake in the pan a minimum of 30 minutes and then invert onto cooling rack. I dust with powdered sugar to serve, but you bet your ass this would be awesome with sweetened whipped cream and a few fresh strawberries sprinkled on top.