Special equipment: 9-inch springform pan with removable bottom
FIRST Preheat oven to 375°F. In a large bowl or food processor, combine butter, flour, and pecans until smooth. Pour batter into a greased, springform pan and place on a baking sheet. Bake until crust begins to brown, about 15-20 minutes. Remove from oven to cool.
NEXT Beat cream on medium speed until soft peaks form; set aside. Beat cream cheese, sugar, and vanilla until fluffy; fold in whipped cream. Spread mixture on top of crust and refrigerate while preparing topping.
LAST In a medium saucepan set over medium-high heat, combine sugar, flour, jello, and water. Cook, stirring constantly, until mixture is thick and clear, about 8 minutes; set aside to cool. Arrange peach slices on top of tart and pour cooled jello mixture over peaches, using a rubber scrapper to spread evenly. Cover with plastic wrap and chill until set, at least 4 hours.