Line a 7-1/2 x 3-1/2x2-inch loaf pan with plastic wrap, extending wrap beyond edges of pan; set aside.
In a medium mixing bowl beat cream cheese and pesto with an electric mixer on medium speed until smooth. Lay 2 slices of the provolone cheese in bottom and slightly up sides of pan. Spread half of the pesto mixture on cheese layer. Repeat layers; top with remaining 2 slices of provolone cheese. Cover surface with plastic wrap. Weight it down with a can of soup or vegetables. Chill overnight.
To serve, remove plastic wrap from top of terrine. Invert onto a serving plate and remove plastic wrap. Cut terrine lengthwise in half. Cut crosswise into 1/2-inch-thick slices. Serve with baguette slices or crackers. If desired, garnish with basil leaves. Makes 24 to 28 servings.