Here is my recipe for a Belgian Double. I was shooting for something like Mardesous.
9 lb Munich Liquid Extract
1 lb Caramunich Malt
1 lb Special B Malt
1 lb Dark Brown Sugar
0.5 lb Light Dry Extract (for 2L yeast starter)
1 oz Goldings, East Kent- 60 min
1 oz Saaz- 5 min
White Labs Belgian Ale Yeast
3.25 gallon boil, 5 gallon batch
Came out to 7.9% alcohol by volume. Is that high enough for you?