Make small slits in the tuna steaks with a knife and insert a sliver of garlic into each slit. Heat a browning dish for 3 minutes on High. Drop in 1T butter and the peeled onions. Heat for 1-2 minutes on High, stirring occasionally, until the onions begin to brown. Pour in the water and wine. Transfer the contents of the browning dish to a large casserole. Add the bay leaf and fish to the casserole, cover loosely and cook for 5 minutes on High. Remove the fish and onions from the casserole and keep them warm. Melt 1T butter in small, deep bowl for 30 seconds on High. Stir in the flour and cook for 1-2 minutes on High or until flour is lightly browned. Pour in the cooking liquid from the fish, and add the tomato paste and thyme. Cook for 2-3 minutes on High, stirring occasionally until thickened. Add the parsley, lemon juice, salt and pepper, and set aside with the fish. Melt the remaining butter in a small casserole on High for 30 seconds. Put in the spinach, cover loosely and cook for 1-2 minutes on High. Spread the spinach onto a serving plate and combine the fish and sauce to re-heat for 30 seconds on High. Arrange the fish and onions on top of the bed of spinach and pour the sauce over to serve.

The Complete Microwave Cookbook. Judith Ferguson and Celia Norman.