In order to design energy efficient cooker-top burners, the stabilization mechanisms of partially premixed flames were investigated. Different design features are assessed with the identical fuel (CH4), fuel flow rate, and load vessel arrangement, but with different levels of primary aeration and flame delivery. k-epsilon Reynolds-averaged Navier-Stokes (RANS) simulations are performed using the modified temperature-composition pdf method and the intrinsic low-dimensional manifold (ILDM) reduction scheme. The results show that the optimum value of the angle of flame delivery is about 30-35 deg. The contact area of the flame cup under the bottom surface depends on the diameter of the burner head which determines the separation of the flames. The traditional solution to reduce the port separations, which is to increase the number of ports, is shown to cause weak flames which extinguish in shorter distances and can have strong tendency to blow off. It also causes significant pressure resistance ahead of the contraction tube and so impairs the primary aeration. In the present study, a new slot profile, named the double-V form, is proposed and shown to be very effective in reducing the gaps between the flames, without creating any further pressure resistance.