Measure the kitchen. Make a paper pattern of the high bar out of kraft paper. Tape it to the floor and walk around it to ensure that it doesn't block the kitchen's traffic flow. Allow enough space around the bar to open the oven, refrigerator and dishwasher doors. Generally, a 48-inch-wide bar seats two people.
Turn the base cabinet you'll use for the bar upside down. Measure the bottom with a tape measure.
Cut a piece of plywood to fit onto the bottom of the cabinet. Sand with 180-grit sandpaper to smooth the cut edges. Wipe with a tack cloth to remove the wood dust.
Paint or stain the plywood to match the cabinet. If you are painting the plywood, brush on a coat of primer and allow to dry. Then brush on two coats of paint and allow to dry according to the manufacturer's instructions. If you are staining the plywood, apply the stain with a rag. Allow the stain to soak into the wood for a few minutes, then remove the excess stain with a rag. After the stain is dry, apply two coats of polyurethane and allow to dry completely.
Draw a bead of construction glue around the bottom of the cabinet. Place the plywood on the cabinet, carefully aligning the sides.
Drill screw holes every six inches around the perimeter, through the plywood and into the base cabinet. Screw the plywood to the base cabinet, using 2-inch wood screws.
Add a table leg connector to each corner of the cabinet. Install two inches from each corner, using the enclosed screws. Mark and drill through the plywood, then screw the brackets to the bottom of the cabinet.
Screw the 4-inch table legs or bun feet into the connectors. Turn the cabinet right side up.
Attach the decorative brackets or corbels to the back of the cabinet, one on each side. Drill through the brackets and into the cabinet according to the manufacturer's directions. Attach the brackets with wood screws.
Place the countertop on top of the cabinet. Align the countertop so that the front and sides overlap the cabinet by two inches and the back side extends 18 inches out, resting on the brackets.
Drill through the cabinet top and into the bottom of the countertop. Attach the countertop to the cabinet with wood screws.