Grease and lightly flour 12 3" tart pans. For pastry: With electric mixer, beat butter, Sugar, almond paste and lemon peel at medium speed until combined. Add egg yolks and beat at high speed until smooth. At low speed, gradually add flour and mix until just blended. Place about 2 tbsp. dough in each tart pan and pat evenly over bottom and sides. Prick bottoms with a fork. Refrigerate 1 hour. Place tart pans on a jelly roll pan and bake at 300' for 40 minutes. Cool in pans 15 minutes then carefully remove from pans and cool completely. For mango mousse: In a small saucepan, sprinkle gelatin over water to soften. Let stand 1 minute. Melt over low heat about 3 minutes, stirring. Cool to room temperature. Cut mango in 1" chunks and puree with 1/4 cup Sugar, lemon juice and rum. Add cooled gel