This is a fully automatic redstone furnace. It fuel goes in the chest on the left, food and ores go in the middle. The food and ores come out cooked in the right chest. To import it into your world, put it so that only the top chest is the only thing above the ground and uncheck the box that says "copy air"

I also made a one command build of it. Put this command into an inpulse command block and make it "always active." Then the furnace will appear 3 blocks to the south.

summon minecraft:falling_block ~ ~1 ~ {id:"minecraft:falling_block",Block:"minecraft:redstone_block",Time:1,Passengers:[{id:"minecraft:falling_block",Block:"minecraft:activator_rail",Time:1,Passengers:
{id:"minecraft:commandblock_minecart",Command:"gamerule commandBlockOutput false"},
{id:"minecraft:commandblock_minecart",Command:"gamerule logAdminCommands false"},
{id:"minecraft:commandblock_minecart",Command:"setblock ~1 ~-5 ~4 minecraft:hopper 3 replace {Items:],id:\"minecraft:hopper\",Lock:\"\"}"},
{id:"minecraft:commandblock_minecart",Command:"setblock ~1 ~-5 ~5 minecraft:dropper 1 replace {Items:[],id:\"minecraft:dropper\",Lock:\"\"}"},
{id:"minecraft:commandblock_minecart",Command:"setblock ~1 ~-4 ~3 minecraft:hopper 3 replace {Items:[],id:\"minecraft:hopper\",Lock:\"\"}"},
{id:"minecraft:commandblock_minecart",Command:"setblock ~1 ~-4 ~4 minecraft:furnace 4 replace {BurnTime:0s,Items:[],id:\"minecraft:furnace\",Lock:\"\"}"},
{id:"minecraft:commandblock_minecart",Command:"setblock ~1 ~-4 ~5 minecraft:dropper 1 replace {Items:[],id:\"minecraft:dropper\",Lock:\"\"}"},
{id:"minecraft:commandblock_minecart",Command:"setblock ~1 ~-3 ~3 minecraft:chest 4 replace {Items:[],id:\"minecraft:chest\",Lock:\"\"}"},
{id:"minecraft:commandblock_minecart",Command:"setblock ~1 ~-3 ~4 minecraft:hopper 0 replace {Items:[],id:\"minecraft:hopper\",Lock:\"\"}"},
{id:"minecraft:commandblock_minecart",Command:"setblock ~1 ~-3 ~5 minecraft:chest 4 replace {Items:[],id:\"minecraft:chest\",Lock:\"\"}"},
{id:"minecraft:commandblock_minecart",Command:"setblock ~1 ~-2 ~4 minecraft:chest 4 replace {Items:[],id:\"minecraft:chest\",Lock:\"\"}"},
{id:"minecraft:commandblock_minecart",Command:"fill ~-1 ~-5 ~5 ~-1 ~-5 ~6 minecraft:redstone_wire"},
{id:"minecraft:commandblock_minecart",Command:"fill ~0 ~-5 ~6 ~0 ~-5 ~8 minecraft:redstone_wire"},
{id:"minecraft:commandblock_minecart",Command:"setblock ~1 ~-5 ~8 minecraft:redstone_wire"},
{id:"minecraft:commandblock_minecart",Command:"setblock ~0 ~-5 ~5 minecraft:unpowered_repeater 1"},
{id:"minecraft:commandblock_minecart",Command:"setblock ~1 ~-5 ~6 minecraft:unpowered_comparator 2 replace {id:\"minecraft:comparator\"}"},
{id:"minecraft:commandblock_minecart",Command:"setblock ~1 ~-5 ~7 minecraft:unpowered_repeater 2"},
{id:"minecraft:commandblock_minecart",Command:"tellraw @p {\"text\":\"Generated with Mamo's \",\"color\":\"yellow\",\"extra\":[{\"text\":\"Structure spawner generator\",\"color\":\"blue\",\"clickEvent\":{\"action\":\"open_url\",\"value\":\"https://github.com/xMamo/Structure-spawner-generator\"},\"hoverEvent\":{\"action\":\"show_text\",\"value\":\"Click here if you want this filter too!\"}},\".\"]}"},
{id:"minecraft:commandblock_minecart",Command:"setblock ~ ~1 ~ minecraft:command_block 0 replace {auto:1b,Command:\"fill ~ ~-3 ~ ~ ~ ~ minecraft:air\"}"},
{id:"minecraft:commandblock_minecart",Command:"kill @e[type=minecraft:commandblock_minecart,r=0]"}
]}]}