Heat oven to 425 degrees F. Grease 12-inch pizza pan with shortening. Unroll dough; place in pan. Starting at center, press out dough to edge of pan, forming 1/2-inch rim. Bake 8 to 10 minutes or until light golden brown.
Meanwhile, in 8-inch skillet, melt butter over medium-high heat. Add bell pepper and onion; cook 3 to 5 minutes, stirring occasionally, until tender.
Sprinkle 1 cup of the cheese evenly over partially baked crust. Top with bell pepper mixture, beef, remaining 1 cup cheese and the tomato slices (be sure beef is completely covered with cheese).
Bake 12 to 18 minutes longer or until crust is deep golden brown. Cut into wedges to serve