This is a school project but I thought it can be fun to all of you cooking people out there, that still use old stoves without timers.
The timer uses different formula for meat, chicken or egg, but also has a separate timer that can be activated manually.

Meat cooking time formula:
1 pounds - 35 min
2 pounds - 45 min
Every extra pound add 15 min
*500f for 15 min. buzzer bips once. than 380f for the rest of the cooking.

Chicken cooking time formula:
1 pounds - 40 min
2 pounds - 60 min
Every extra pound add 10 min
*400f for the whole time. ignor buzzer bip after 15 first min.

Egg cooking time formula:
Soft egg - 5 min
Hard egg - 11 min

Step 1: Materials

6 * small buttons - radio shack
switch - radio shack
back lit LCD display - parallax.com
buzzer
potentiometer
knob
a box

Universal Solderless Breadboard
6 * 470 Kohms resistors (red, black, orange, gold)
1 * 2 Kohms resistors (red, black, red, gold)
2 * .1ÃÂµF capacitors
1 * voltage regulator (7805)

Microchip microcontroller - pic16F819- digikey.com
pic data sheet
If you don't have a pic programer or the Compiler and you want to purchase them. i recommend these from Melabs:
U2 programer
PicBasic Compiler