Mahi Mahi with Wine and Shallot Ginger Glaze

2 pound Mahi Mahi fillets
6 shallots, coarsely chopped
4 quarter-size slices fresh unpeeled ginger
1 clove garlic
3 tbsp unsalted butter
1/2 cup chicken broth
4 tsp cornstarch
1/3 cup dry white wine
1 tbsp fresh lemon juice
2 tsp grated lemon zest
1/2 tsp freshly ground black pepper

Preheat grill or broiler; spray a grill pan with non-stick cooking spray and arrange the Mahi Mahi fillets on top. In a food processor, mince shallots, ginger and garlic.
In a small frypan, melt butter. Add shallot-ginger mixture and cook, stirring until just golden, 8 - 10 minutes. Remove frypan from heat.
Brush Mahi Mahi fillets with half the ginger-shallot mixture. Grill 3 cm from heat, turning once, until lightly coloured and the flesh just flakes when tested with a fork, about 6 minutes.
In a small bowl, blend together chicken broth and cornstarch. Return frypan to medium heat and stir in wine, lemon juice, zest, and pepper.
Bring to a boil, add cornstarch mixture and return to a boil, stirring constantly. Reduce heat to medium-low and simmer, stirring occasionally, for 1 minute or until thickened and slightly glossy.
Transfer fillets to plates and drizzle shallot-ginger glaze over them. Serve immediately