The glass on your oven door is tempered to resist the heat of cooking. The glass is not tempered to withstand a casserole dish falling on the glass. Glass will break and when glass breaks you will need to replace it. Appliance repair facilities carry replacement oven door glass. You will need to provide them with your make and model of oven. Once you have the replacement glass, you will need to remove the oven door to replace the inner glass.
Disconnect the oven's power cord from the electrical wall outlet. Although you will not be working directly on electrical components, it is good safe practice to disconnect the power source from appliances before making any repairs.
Open the oven door halfway. Place a large nail or screw into the empty hole on the side hinge along the side of the door. A hinge is on each side of the door. The nail will keep the hinge from closing into the oven after you remove the door. Close the door as far as the nails will allow.
Grab the sides of the oven door with your hands and pull the door straight up until the door stops. Push the top of the door toward the floor and pull the door toward you to release the door from the hinges. Lay a sheet on the floor and place the door on the sheet with the handle side facing the floor.
Remove the screws that secure the inner liner to the outer door with a Phillips-head screwdriver. Some models only have two screws at the top edge of the liner. Other models will have up to six screws on the panel and two on each side of the door. Lift the inner panel up and slide the inner panel away from the outer panel.
Use the Phillips-head screwdriver to remove the two inner screws that secure the door handle to the oven door. Lift up the oven door and pull the handle and the top trim behind the handle away from the door.
Remove the three screws on the bottom edge of the door that secure the bottom trim to the oven door with the Phillips-head screwdriver. Pull the bottom trim off of the door. Locate the two screws that secure the right side hinge assembly. The hinge assembly is the part on the inside of the oven door that the hinge slides into. The screws are on the bottom edge of the door directly under the hinge assembly. Remove the screws with a Phillips-head screwdriver and pull the hinge assembly out of the door.
Fold the door insulation back and pull the broken oven door glass and frame out of the door. Put leather gloves on your hands and pull the broken glass out of the metal frame. Place the replacement glass into the frame and set the glass and frame back into the oven door. Position the door insulation back over the edges of the metal frame.
Slide the hinge assembly back into position and secure the hinge assembly to the oven door using the two retaining screws. Reattach the bottom trim and secure the trim to the oven door with the retaining screws.
Lift the top of the oven door up slightly and line the upper trim and door handle into position. Secure the upper trim and door handle by attaching the retaining screws from the inside of the door. Tighten the screws with a Phillips-head screwdriver but do not over-tighten.
Slide the inner panel back over the oven door and secure the inner panel to the door with the retaining screws. Pick the oven door up by grabbing the door at the sides with both hands.
Place the bottom edge of the oven door over the two side hinges on the oven. Line the oven door slots over the hinge pins and push the door down until the hinge pins lock into the oven door. Open the door slightly and pull the nails out of the hinges.
Close the oven door and plug the power cord to the oven back into the electrical wall outlet.