= 4400 - 19% taxes= 3500MINUS 1 worker 2000zl
Correct me if I am wrong, but the salaries your business pays should be deducted from your gross revenue before tax, not net revenue after tax (unless you are paying your employees cash under the table)...
So to correct:
4400 - 2000 (salary of employee) = 2400
Less 19% tax = 1900 (actually 1944).
So you pay around PLN 400 extra for declaring your tax on the wrong amount.
Another thing you should know, if a prepared food item costs you 50% of its retail price just in raw material, then you are not on top of your game. Cost of raw material in the restaurant industry (particularly in fast food) should not exceed 25% of the retail price (and in some cases, can be as low as 10%).
For example, a chicken kebab:
Chicken 100g: 2.00 (for ready skinless chicken breast bought retail, so it can be reduced by buying whole sale and more so by buying whole chicken and deboning it yourself)
Flat Bread: 0.15 (can be reduced by half if you bake your own bread)
Seasoning: 0.15 (sauce, spices etc.)
Total: PLN 2.50
However, I think your estimate of energy cost is a bit conservative. With the grill fired up several hours a day, energy may very well be your highest overhead.