Whisk 1 tablespoon each butter and flour in an ovenproof skillet over medium-high heat, 1 minute. Add 1 1/4 cups low-fat milk; whisk until boiling. Stir in a 9-ounce package thawed frozen artichoke hearts, 1 cup thawed frozen peas and 1/2 teaspoon each salt and lemon zest; bring to a simmer. Top with grated parmesan and broil until golden.
Photograph by Antonis Achilleos