Cooking English Muffins Without Burning

I've been using this recipe but I can't get the centers cooked without burning the outside. Does anyone have any suggestions? What am I missing?

I cook the muffins in a 10-inch skillet on a gas stove over medium heat.

Here are the techniques I've tried:

1. first time, heat was too high, and the outside began to burn. Turned it down, flipped it, and cooked the other side for 6 minutes. Mushy inside.

2. lower heat. Cooked each side for 8 minutes. Surfaces were dark brown, but not burnt. Mushy inside.

3. still lower heat. Cooked each side for 10 minutes. Surfaces were dark brown, but not burnt. Mushy inside.

4. same heat as 3; online suggestion was to finish in a 350 degree oven for 10 minutes. Outside edges were crisp instead of soft. Mushy inside.

5. still lower heat. Cooked one side for 6 minutes, flipped, cooked for 6 minutes, flipped, 6 minutes, flipped, 6 minutes. (total 12 minutes per side). Surfaces were dark brown, but not burnt. Mushy inside.

When I say "mushy" I mean that it's undercooked in the middle.

In all cases, I let the muffins cool completely before I cut them open, to use the residual heat to finish cooking.

I've been broiling them after cutting them open, and we really like the flavor. But cutting each muffin open and toasting it immediately after griddling just isn't right. <g>