Happy Mother's day to my wife, who loves leeks and spinach. I developed this dish with that in mind: Cajun flavored shrimp rest on a smooth bed of creamy polenta cooked with savory leeks, beside cooked spinach. The shrimp are bathed in a glazey wine sauce made with the reserved shrimp shells - a flavor that can only be found by cooking the shells themselves. The rich shell-wine sauce truly transforms this dish. For the shrimp: 2 Tbsp butter plus 2 Tbsp olive oil 1 lb shrimp (about 15-16 large), peeled, deveined, shells reserved 3 Tbsp favorite Cajun seasoning 3 cloves garlic, passed through a garlic press 1/4 tsp crushed red pepper flakes (or to taste) Zest of 1 lemon 1 Tbsp olive oil For the shell broth: 2 Tbsp olive oil 1 cup dry white wine 1 Tbsp cornstarch dissolved in 2 Tbsp cold water For the leek polenta: 2 Tbsp butter 1 leek cleaned and finely diced 1/2 cup polenta or coarse cornmeal (or you could also use grits) 2 cups chicken broth 1/2 cup heavy cream 1/2 cup grated parme...