For my son's birthday last summer, I made felt pizza (at his request). First I made a paper pattern for the pizza, cheese and sauce. The crust was two wedges of tan felt for each piece; the cheese was a single wedge. For the sauce I opted for arcs instead of continuing it under the whole piece of cheese. I cut out my pieces and my pepperoni, mushrooms, olives and green peppers. This is more vegetables then my children would truly eat on a pizza, but plain cheese would have just looked boring.
The first thing I sewed was the toppings onto the cheese (zig-zag or straight stitch, whichever is easier for each piece). Then I sewed the arc of sauce onto the cheese; then the whole thing went on a piece of crust. I sewed a second piece of crust on the two straight sides with the wrong sides together.
I turned it right side out, then sewed a line about 3/4 inch away from the curved edge, right next to the sauce. This is the inside seam of the crust, which is the only portion of the pizza that is stuffed. I zig-zagged over the curved edge, but left about an inch at the end. I stuffed the crust through this hole, using a pencil, then went back and finished zig-zagging the last inch.
Repeat 3 more times. All done!